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04 Aug 2020 at 01:36
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Bibliography on: Corvids: Behavior


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RJR: Recommended Bibliography 04 Aug 2020 at 01:36 Created: 

Corvids: Behavior

Audubon Magazine: Members of the crow family, known as the corvids, are among the smartest birds in the world. Some are capable of using tools, playing tricks, teaching each other new things, even holding "funerals." And yet there's still much we don't know about these fascinating, sometimes confounding creatures. All corvids have relatively big brains for their size. But while a seed storer like a Pinyon Jay or a nutcracker has a huge hippocampus — a region involved in memory — crows and ravens are more like primates. They have exceptionally large forebrains, the domain of analytical thought, higher-level sensory processing, and flexible behavior.

Created with PubMed® Query: (behavior OR behaviour OR ethology) AND \(corvus[TIAB] OR corvid[TIAB] OR OR corvids[TIAB] OR corvidae[TIAB] OR crow[TIAB] OR crows[TIAB] OR raven[TIAB] OR ravens[TIAB] OR jay[TIAB] OR jays[TIAB] OR magpie[TIAB] OR magpies[TIAB] OR jackdaw[TIAB] OR jackdaws[TIAB]) NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)


RevDate: 2020-07-30
CmpDate: 2020-07-30

Congdon JV, Hahn AH, Filippi P, et al (2019)

Hear them roar: A comparison of black-capped chickadee (Poecile atricapillus) and human (Homo sapiens) perception of arousal in vocalizations across all classes of terrestrial vertebrates.

Journal of comparative psychology (Washington, D.C. : 1983), 133(4):520-541.

Recently, evidence for acoustic universals in vocal communication was found by demonstrating that humans can identify levels of arousal in vocalizations produced by species across three biological classes (Filippi et al., 2017). Here, we extend this work by testing whether two vocal learning species, humans and chickadees, can discriminate vocalizations of high and low arousal using operant discrimination go/no-go tasks. Stimuli included vocalizations from nine species: giant panda, American alligator, common raven, hourglass treefrog, African elephant, Barbary macaque, domestic pig, black-capped chickadee, and human. Subjects were trained to respond to high or low arousal vocalizations, then tested with additional high and low arousal vocalizations produced by each species. Chickadees (Experiment 1) and humans (Experiment 2) learned to discriminate between high and low arousal stimuli and significantly transferred the discrimination to additional panda, human, and chickadee vocalizations. Finally, we conducted discriminant function analyses using four acoustic measures, finding evidence suggesting that fundamental frequency played a role in responding during the task. However, these analyses also suggest roles for other acoustic factors as well as familiarity. In sum, the results from these studies provide evidence that chickadees and humans are capable of perceiving arousal in vocalizations produced by multiple species. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

RevDate: 2020-07-30
CmpDate: 2020-07-30

Cumbo E, Cumbo S, Torregrossa S, et al (2019)

Treatment Effects of Vortioxetine on Cognitive Functions in Mild Alzheimer's Disease Patients with Depressive Symptoms: A 12 Month, Open-Label, Observational Study.

The journal of prevention of Alzheimer's disease, 6(3):192-197.

BACKGROUND/OBJECTIVES: depressive symptoms are common in Alzheimer's disease(AD). Aim of the study was to investigate the efficacy of vortioxetine compared with other conventional antidepressants on cognitive functions in AD patients with depressive symptoms.

DESIGN: Prospective, randomized, 12 month, parallel-group study.

SETTING: All participants were evaluated on-site at Neurodegenerative Disorders Unit, ASP2 Caltanissetta(Italy).

PARTICIPANTS: 108(71 female, 37 male) AD patients with depression(mean age 76.7 ± 4.3).

INTERVENTION: Randomized subjects received vortioxetine, 15 mg/day(n=36) or other common antidepressants(n=72).

MEASURES: Primary outcome was change from baseline in the MMSE; secondary outcomes were change in Attentive Matrices, Raven Coloured Progressive Matrices, Digit Span, HAM-D and Cornell scale.

RESULTS: Statistically significant improvement vs. controls was observed for vortioxetine on most of the cognitive tests and showed significantly baseline-to-endpoint reduction in both HAM-D and Cornell total scores.The most commonly reported adverse events were nausea and headache for votioxetine; nausea in the control group.

CONCLUSIONS: Vortioxetine had a beneficial effect on cognition and mood in elderly AD patients and was safe and well tolerated.

RevDate: 2020-07-18

Lee CY, Peralta-Sánchez JM, Martínez-Bueno M, et al (2020)

The gut microbiota of brood parasite and host nestlings reared within the same environment: disentangling genetic and environmental effects.

The ISME journal pii:10.1038/s41396-020-0719-y [Epub ahead of print].

Gut microbiota are essential for host health and survival, but we are still far from understanding the processes involved in shaping their composition and evolution. Controlled experimental work under lab conditions as well as human studies pointed at environmental factors (i.e., diet) as the main determinant of the microbiota with little evidence of genetic effects, while comparative interspecific studies detected significant phylogenetic effects. Different species, however, also differ in diet, feeding behavior, and environmental characteristics of habitats, all of which also vary interspecifically, and, therefore, can potentially explain most of the detected phylogenetic patterns. Here, we take advantage of the reproductive strategy of avian brood parasites and investigate gut microbiotas (esophageal (food and saliva) and intestinal) of great spotted cuckoo (Clamator glandarius) and magpie (Pica pica) nestlings that grow in the same nests. We also estimated diet received by each nestling and explored its association with gut microbiota characteristics. Although esophageal microbiota of magpies and great spotted cuckoos raised within the same environment (nest) did not vary, the microbiota of cloacal samples showed clear interspecific differences. Moreover, diet of great spotted cuckoo and magpie nestlings explained the microbiota composition of esophageal samples, but not of cloaca samples. These results strongly suggest a genetic component determining the intestinal microbiota of host and parasitic bird species, indicating that interspecific differences in gut morphology and physiology are responsible for such interspecific differences.

RevDate: 2020-07-18

Wei W, Zhen Q, Tang Z, et al (2020)

Risk assessment in the plateau pika (Ochotona curzoniae): intensity of behavioral response differs with predator species.

BMC ecology, 20(1):41 pii:10.1186/s12898-020-00309-3.

BACKGROUND: The ability of a prey species to assess the risk that a predator poses can have important fitness advantages for the prey species. To better understand predator-prey interactions, more species need to be observed to determine how prey behavioral responses differ in intensity when approached by different types of predators. The plateau pika (Ochotona curzoniae) is preyed upon by all predators occurring in its distribution area. Therefore, it is an ideal species to study anti-predator behavior. In this study, we investigated the intensity of anti-predator behavior of pikas in response to visual cues by using four predator species models in Maqu County on the eastern Qinghai-Tibetan Plateau.

RESULTS: The behavioral response metrics, such as Flight Initiation Distance (FID), the hiding time and the percentage of vigilance were significantly different when exposed to a Tibetan fox, a wolf, a Saker falcon and a large-billed crow, respectively. Pikas showed a stronger response to Saker falcons compared to any of the other predators.

CONCLUSIONS: Our results showed that pikas alter their behavioral (such as FID, the hiding time and the vigilance) response intensity to optimally balance the benefits when exposed to different taxidermy predator species models. We conclude that pikas are able to assess their actual risk of predation and show a threat-sensitive behavioral response.

RevDate: 2020-07-14

Baciadonna L, Cornero FM, Emery NJ, et al (2020)

Convergent evolution of complex cognition: Insights from the field of avian cognition into the study of self-awareness.

Learning & behavior pii:10.3758/s13420-020-00434-5 [Epub ahead of print].

Pioneering research on avian behaviour and cognitive neuroscience have highlighted that avian species, mainly corvids and parrots, have a cognitive tool kit comparable with apes and other large-brained mammals, despite conspicuous differences in their neuroarchitecture. This cognitive tool kit is driven by convergent evolution, and consists of complex processes such as casual reasoning, behavioural flexibility, imagination, and prospection. Here, we review experimental studies in corvids and parrots that tested complex cognitive processes within this tool kit. We then provide experimental examples for the potential involvement of metacognitive skills in the expression of the cognitive tool kit. We further expand the discussion of cognitive and metacognitive abilities in avian species, suggesting that an integrated assessment of these processes, together with revised and multiple tasks of mirror self-recognition, might shed light on one of the most highly debated topics in the literature-self-awareness in animals. Comparing the use of multiple assessments of self-awareness within species and across taxa will provide a more informative, richer picture of the level of consciousness in different organisms.

RevDate: 2020-07-02

Boucherie PH, Blum C, T Bugnyar (2020)

Effect of rearing style on the development of social behaviour in young ravens (Corvus corax).

Ethology : formerly Zeitschrift fur Tierpsychologie, 126(6):595-609.

Early social experiences can affect the development and expression of individual social behaviour throughout life. In particular, early-life social deprivations, notably of parental care, can later have deleterious consequences. We can, therefore, expect rearing procedures such as hand-raising-widely used in ethology and socio-cognitive science-to alter the development of individual social behaviour. We investigated how the rearing style later affected (a) variation in relationship strength among peers and (b) individuals' patterns of social interactions, in three captive groups of juvenile non-breeders consisting of either parent-raised or hand-raised birds, or a mix of both rearing styles. In the three groups, irrespectively of rearing style: strongest relationships (i.e., higher rates of association and affiliations) primarily emerged among siblings and familiar partners (i.e., non-relatives encountered in early life), and mixed-sex and male-male partners established relationships of similar strength, indicating that the rearing style does not severely affect the quality and structure of relationships in young ravens. However, compared to parent-raised ravens, hand-raised ravens showed higher connectedness, i.e., number of partners with whom they mainly associated and affiliated, but formed on average relationships of lower strength, indicating that social experience in early life is not without consequences on the development of ravens' patterns of social interaction. The deprivation of parental care associated with the presence of same-age peers during hand-raising seemed to maximize ravens' propensity to interact with others, indicating that besides parents, interactions with same-age peers matter. Opportunities to interact with, and socially learn from peers, might thus be the key to the acquisition of early social competences in ravens.

RevDate: 2020-07-02
CmpDate: 2020-07-02

McMillan JR, Marcet PL, Hoover CM, et al (2019)

Feeding Success and Host Selection by Culex quinquefasciatus Say Mosquitoes in Experimental Trials.

Vector borne and zoonotic diseases (Larchmont, N.Y.), 19(7):540-548.

Arthropod vector feeding preferences are defined as an overutilization of a particular host species given its abundance in relationship to other species in the community. Numerous methods exist to quantify vector feeding preferences; however, controlled host choice experiments are generally an underutilized approach. In this report, we present results from controlled vector host choice experiments using Culex quinquefasciatus Say (Diptera: Culicidae) mosquitoes and wild avian hosts identified as important contributors to West Nile virus (WNv) transmission in Atlanta, Georgia, United States. In each experiment, we allowed lab-reared F1Cx. quinquefasciatus to feed freely overnight on two avian individuals of a different species (i.e., northern cardinals, American robins, blue jays, brown thrashers, and gray catbirds). We then estimated WNv transmission potential using vectorial capacity and R0. We found that mosquito blood feeding success was extremely variable among experimental replicates and that patterns of host choice only occasionally aggregated to a particular bird species. Vectorial capacity was highest for American robins and blue jays due to these species' higher reservoir competence for WNv and greater probabilities of mosquito selection of these species. Despite species-specific differences in vectorial capacity, total community capacity was similar among species pairs. R0 estimates were qualitatively similar to capacity, and R0 was below and above unity across species pairs. Our results provide empirical evidence that C. quinquefasciatus is an opportunistic blood feeder and highlight how variability in vector-host contact rates as well as host community composition can influence the likelihood of WNv transmission in avian communities.

RevDate: 2020-07-01
CmpDate: 2020-07-01

Lambert ML, M Osvath (2020)

Investigating information seeking in ravens (Corvus corax).

Animal cognition, 23(4):671-680.

Measuring the responses of non-human animals to situations of uncertainty is thought to shed light on an animal's metacognitive processes; namely, whether they monitor their own knowledge states. For example, when presented with a foraging task, great apes and macaques selectively seek information about the location of a food item when they have not seen where it was hidden, compared to when they have. We presented this same information seeking task to ravens, in which a food item was hidden in one of three containers, and subjects could either watch where the food was hidden, infer its location through visual or auditory clues, or were given no information. We found that unlike several ape species and macaques, but similar to capuchin monkeys, the ravens looked inside at least one tube on every trial, but typically only once, inside the baited tube, when they had either witnessed it being baited or could visually infer the reward's location. In contrast, subjects looked more often within trials in which they had not witnessed the baiting or were provided with auditory cues about the reward's location. Several potential explanations for these ceiling levels of looking are discussed, including how it may relate to the uncertainty faced by ravens when retrieving food caches.

RevDate: 2020-07-01
CmpDate: 2020-07-01

Miller R, Frohnwieser A, Schiestl M, et al (2020)

Delayed gratification in New Caledonian crows and young children: influence of reward type and visibility.

Animal cognition, 23(1):71-85.

Self-control underlies cognitive abilities such as decision making and future planning. Delay of gratification is a measure of self-control and involves obtaining a more valuable outcome in the future by tolerating a delay or investing a greater effort in the present. Contextual issues, such as reward visibility and type, may influence delayed gratification performance, although there has been limited comparative investigation between humans and other animals, particularly non-primate species. Here, we adapted an automated 'rotating tray' paradigm used previously with capuchin monkeys to test for delay of gratification ability that requires little pre-test training, where the subject must forgo an immediate, less preferred reward for a delayed, more preferred one. We tested New Caledonian crows and 3-5-year-old human children. We manipulated reward types to differ in quality or quantity (Experiments 1 and 2) as well as visibility (Experiment 2). In Experiments 1 and 2, both species performed better when the rewards varied in quality as opposed to quantity, though performed above chance in both conditions. In Experiment 1, both crows and children were able to delay gratification when both rewards were visible. In Experiment 2, 5-year-old children outperformed 3- and 4-year olds, though overall children still performed well, while the crows struggled when reward visibility was manipulated, a result which may relate to difficulties in tracking the experimenters' hands during baiting. We discuss these findings in relation to the role of contextual issues on self-control when making species comparisons and investigating the mechanisms of self-control.

RevDate: 2020-06-16

Chakarov N, Kampen H, Wiegmann A, et al (2020)

Blood parasites in vectors reveal a united blackfly community in the upper canopy.

Parasites & vectors, 13(1):309 pii:10.1186/s13071-020-04177-0.

BACKGROUND: The behaviour of blood-sucking arthropods is a crucial determinant of blood protozoan distribution and hence of host-parasite coevolution, but it is very challenging to study in the wild. The molecular identification of parasite lineages in vectors can be a useful key to understand the behaviour and transmission patterns realised by these vectors.

METHODS: In this study, we collected blackflies around nests of three raptor species in the upper forest canopy in central Europe and examined the presence of vertebrate DNA and haemosporidian parasites in them. We molecularly analysed 156 blackfly individuals, their vertebrate blood meals, and the haemosporidian parasite lineages they carried.

RESULTS: We identified nine species of Simulium blackflies, largely belonging to the subgenera Nevermannia and Eusimulium. Only 1% of the collected specimens was visibly engorged, and only 4% contained remains of host DNA. However, in 29% of the blackflies Leucocytozoon lineages were identified, which is evidence of a previous blood meal on an avian host. Based on the known vertebrate hosts of the recorded Leucocytozoon lineages, we can infer that large and/or abundant birds, such as thrushes, crows, pigeons, birds of prey, owls and tits are the main targets of ornithophilic blackflies in the canopy. Blackfly species contained similar proportions of host group-specific parasite lineages and thus do not appear to be associated with particular host groups.

CONCLUSIONS: The Leucocytozoon clade infecting thrushes, crows, and pigeons present in most represented blackfly species suggests a lack of association between hosts and blackflies, which can increase the probability of host switches of blood parasites. However, the composition of the simuliid species differed between nests of common buzzards, goshawks and red kites. This segregation can be explained by coinciding habitat preferences between host and vector, and may lead to the fast speciation of Leucocytozoon parasites. Thus, subtle ecological preferences and lack of host preference of vectors in the canopy may enable both parasite diversification and host switches, and enforce a habitat-dependent evolution of avian malaria parasites and related haemosporidia.

RevDate: 2020-06-02

Wang L, Luo Y, Wang H, et al (2020)

Azure-winged magpies fail to understand the principle of mirror imaging.

Behavioural processes pii:S0376-6357(19)30396-1 [Epub ahead of print].

Mirror self-recognition (MSR) is considered a crucial step in the emergence of self-cognition. The MSR paradigm has become a standard method for evaluating self-cognition in several species. For example, Eurasian magpies and Indian house crows have passed the mark test for self-cognition, whereas efforts to find MSR in other corvid species have failed. However, no literature has conducted MSR tests on azure-winged magpies, a species of corvids. Therefore, the current research aimed to investigate the MSR behaviours of azure-winged magpies upon looking into a mirror for the first time. The study included four tests: (1) mirror preference and standardised mirror exploration, (2) single vertical mirror test, (3) mark test and (4) mirror-triggered search test. The azure-winged magpies displayed immense curiosity towards the mirror and their images in the mirror in Test 1&2. In the subsequent mark tests, they failed to recognise themselves in the mirror and regarded their images as conspecifics. Behaviour analysis showed no significant difference between marked and unmarked behaviours. Finally they seemed to infer the presence of bait from the image in the mirror, but were found to fail to understand that the location of the bait in the mirror was the same as that in the real world. For a better insight into the MSR behaviour of azure-winged magpies, research studies involving prolonged mirror exposure and training are recommended.

RevDate: 2020-05-28

Brecht KF, Müller J, A Nieder (2020)

Carrion crows (Corvus corone corone) fail the mirror mark test yet again.

Journal of comparative psychology (Washington, D.C. : 1983) pii:2020-37266-001 [Epub ahead of print].

The mirror mark test is generally considered to be an indicator of an animal's ability to recognize itself in the mirror. For this test, an animal is confronted with a mirror and has a mark placed where it can see the mark only with the help of the mirror. When the animal extensively touches or interacts with the mark, compared with control conditions, the mirror mark test is passed. Many nonhuman animal species have been tested, but few have succeeded. After magpies and Indian house crows passed, there has been a sustained interest to find out whether other corvids would pass the mirror mark test. Here, we presented 12 carrion crows (Corvus corone corone) with the mirror mark test. There was no significant increase of mark-directed behavior in the mirror mark test, compared with control conditions. We find very few occasions of mark-directed behaviors and have to interpret them in the context of self-directed behavior more generally. In addition, we show that our crows were motivated to interact with a mark when it was visible to them without the aid of a mirror. We conclude that our crows fail the test, and thereby replicate previous studies showing a similar failure in corvids, and crows in particular. Because our study adds to the growing literature of corvids failing the mirror mark test, the issue of mirror self-recognition in these birds remains controversial. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

RevDate: 2020-05-21

Clarke MJ, Fraser EE, IG Warkentin (2020)

Fine spatial-scale variation in scavenger activity influences avian mortality assessments on a boreal island.

PloS one, 15(5):e0233427 pii:PONE-D-19-28121.

Bird-window collisions are the second leading cause of human-related avian mortality for songbirds in Canada. Our ability to accurately estimate the number of fatalities caused by window collisions is affected by several biases, including the removal of carcasses by scavengers prior to those carcasses being detected during surveys. We investigated the role of scavenger behavior in modifying perceived carcass removal rate while describing habitat-specific differences for the scavengers present in a relatively scavenger-depauperate island ecosystem. We used motion activated cameras to monitor the fate of hatchling chicken carcasses placed at building (under both windows and windowless walls) and forest (open and closed canopy) sites in western Newfoundland, Canada. We recorded the identity of scavengers, timing of events, and frequency of repeat scavenging at sites. Using 2 treatments, we also assessed how scavenging varied with 2 levels of carcass availability (daily versus every third day). Scavenger activities differed substantially between forest and building sites. Only common ravens (Corvus corax) removed carcasses at building sites, with 25 of 26 removals occurring under windows. Burying beetles (Nicrophorus spp.) dominated scavenging at forest sites (14 of 18 removals), completely removing carcasses from sight in under 24 hours. Availability had no effect on removal rate. These findings suggest that ravens look for carcasses near building windows, where bird-window collision fatalities create predictable food sources, but that this learning preceded the study. Such behavior resulted in highly heterogeneous scavenging rates at fine spatial scales indicating the need for careful consideration of carcass and camera placement when monitoring scavenger activity. Our observations of burying beetle activity indicate that future studies investigating bird collision mortality near forested habitats and with infrequent surveys, should consider local invertebrate community composition during survey design. The high incidence of invertebrate scavenging may compensate for the reduced vertebrate scavenger community of insular Newfoundland.

RevDate: 2020-05-18
CmpDate: 2020-05-12

Miller R, Gruber R, Frohnwieser A, et al (2020)

Decision-making flexibility in New Caledonian crows, young children and adult humans in a multi-dimensional tool-use task.

PloS one, 15(3):e0219874.

The ability to make profitable decisions in natural foraging contexts may be influenced by an additional requirement of tool-use, due to increased levels of relational complexity and additional work-effort imposed by tool-use, compared with simply choosing between an immediate and delayed food item. We examined the flexibility for making the most profitable decisions in a multi-dimensional tool-use task, involving different apparatuses, tools and rewards of varying quality, in 3-5-year-old children, adult humans and tool-making New Caledonian crows (Corvus moneduloides). We also compared our results to previous studies on habitually tool-making orangutans (Pongo abelii) and non-tool-making Goffin's cockatoos (Cacatua goffiniana). Adult humans, cockatoos and crows, but not children and orangutans, did not select a tool when it was not necessary, which was the more profitable choice in this situation. Adult humans, orangutans and cockatoos, but not crows and children, were able to refrain from selecting non-functional tools. By contrast, the birds, but not the primates tested, struggled to attend to multiple variables-where two apparatuses, two tools and two reward qualities were presented simultaneously-without extended experience. These findings indicate: (1) in a similar manner to humans and orangutans, New Caledonian crows and Goffin's cockatoos can flexibly make profitable decisions in some decision-making tool-use tasks, though the birds may struggle when tasks become more complex; (2) children and orangutans may have a bias to use tools in situations where adults and other tool-making species do not.

RevDate: 2020-05-14

Soler M, Colmenero JM, Pérez-Contreras T, et al (2020)

Replication of the mirror mark test experiment in the magpie (Pica pica) does not provide evidence of self-recognition.

Journal of comparative psychology (Washington, D.C. : 1983) pii:2020-31404-001 [Epub ahead of print].

Self-recognition in animals is demonstrated when individuals pass the mark test. Formerly, it was thought that self-recognition was restricted to humans, great apes, and certain mammals with large brains and highly evolved social cognition. However, 1 study showed that 2 out of 5 magpies (Pica pica) passed the mark test, suggesting that magpies have a similar level of cognitive abilities to great apes. The scientific advancement depends on confidence in published science, and this confidence can be reached only after rigorous replication of published studies. Here, we present a close replication of the magpie study but using a larger sample size while following a very similar experimental protocol. Like the previous study, in our experiment, magpies showed both social and self-directed behavior more frequently in front of the mirror versus a control cardboard stimulus. However, during the mark test, self-directed behavior proved more frequent in front of the cardboard than in the mirror. Thus, our replication failed to confirm the previous results. Close replications, while not disproving an earlier study, identify results that should be considered with caution. Therefore, more replication studies and additional experimental work is needed to unambiguously demonstrate that magpies are consistently able to pass the mark test. The existence of compelling evidence of self-recognition in other corvid species is discussed in depth. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

RevDate: 2020-05-06

Gill LF, van Schaik J, von Bayern AMP, et al (2020)

Genetic monogamy despite frequent extrapair copulations in "strictly monogamous" wild jackdaws.

Behavioral ecology : official journal of the International Society for Behavioral Ecology, 31(1):247-260.

"Monogamy" refers to different components of pair exclusiveness: the social pair, sexual partners, and the genetic outcome of sexual encounters. Avian monogamy is usually defined socially or genetically, whereas quantifications of sexual behavior remain scarce. Jackdaws (Corvus monedula) are considered a rare example of strict monogamy in songbirds, with lifelong pair bonds and little genetic evidence for extrapair (EP) offspring. Yet jackdaw copulations, although accompanied by loud copulation calls, are rarely observed because they occur visually concealed inside nest cavities. Using full-day nest-box video surveillance and on-bird acoustic bio-logging, we directly observed jackdaw sexual behavior and compared it to the corresponding genetic outcome obtained via molecular parentage analysis. In the video-observed nests, we found genetic monogamy but frequently detected forced EP sexual behavior, accompanied by characteristic male copulation calls. We, thus, challenge the long-held notion of strict jackdaw monogamy at the sexual level. Our data suggest that male mate guarding and frequent intrapair copulations during the female fertile phase, as well as the forced nature of the copulations, could explain the absence of EP offspring. Because EP copulation behavior appeared to be costly for both sexes, we suggest that immediate fitness benefits are an unlikely explanation for its prevalence. Instead, sexual conflict and dominance effects could interact to shape the spatiotemporal pattern of EP sexual behavior in this species. Our results call for larger-scale investigations of jackdaw sexual behavior and parentage and highlight the importance of combining social, sexual, and genetic data sets for a more complete understanding of mating systems.

RevDate: 2020-05-05
CmpDate: 2020-05-05

Huerta-Franco MR, Vargas-Luna M, Somoza X, et al (2019)

Gastric responses to acute psychological stress in climacteric women: a pilot study.

Menopause (New York, N.Y.), 26(5):469-475.

OBJECTIVE: Women exhibit reduced ovarian sex hormones during the menopausal period that result in well-known physical and psychological symptoms. However, symptoms related to gastric motility (GM) have not been thoroughly investigated. We hypothesized that stress response gastric motility (SRGM) is lower in postmenopausal (PM) and perimenopausal (PERIM) women than in premenopausal (PREM) women. Estrogenic decline leads to neuroendocrine changes in different areas of the brain. These changes can result in hypothalamic vasomotor symptoms, disorders in eating behaviours, and altered blood pressure, in addition to psychological disorders such as stress, anxiety, depression, and irritability related to alterations in the limbic system.

METHODS: In this pilot study, 55 PREM, PERIM, and PM women were clinically evaluated using the Nowack stress profile (SP) and State-Trait Anxiety Inventory (STAI). GM was assessed via electrical bioimpedance using two psychological stress tests (Stroop and Raven tests).

RESULTS: Basal SP and STAI-anxiety test scores were similar among the three groups of women (P > 0.05). PERIM women had lower GM in the basal state (P < 0.05) than did other women. PREM and PM women had significantly decreased GM during the stress tests (P < 0.05). However, PERIM did not exhibit GM changes during stress tests (P > 0.05).

CONCLUSION: Changes in sex hormones during PERIM may affect GM and SRGM.

RevDate: 2020-04-24
CmpDate: 2020-04-24

Matsui H, EI Izawa (2019)

Rapid adjustment of pecking trajectory to prism-induced visual shifts in crows as compared with pigeons.

The Journal of experimental biology, 222(Pt 4): pii:jeb.182345.

Pecking in birds is analogous to reaching and grasping movements in primates. Earlier studies on visuomotor control in birds, which were conducted mostly in pigeons, suggested that avian pecking is controlled feedforwardly, and is out of the control of visual guidance during movement. However, recent studies using crows suggested a role of vision in pecking control during movement. To unveil what visuomotor mechanisms underlie the flexibility of pecking in crows, we examined whether pigeons and crows adjust their pecking to the visual distortion induced by prisms. Because prisms induce visual shifts of object positions, birds were required to adjust their movements. Pecking kinematics were examined before and after attaching prisms in front of the birds' eyes. Analysis of lateral deviation caused by the prisms showed that crows rapidly adjusted their pecking trajectories, but pigeons did so slowly. Angular displacement also increased in pigeons after attachment of the prism, but decreased in crows. These responses to prisms were consistent among individuals in pigeons but varied in crows, though the adjustment of pecking commonly succeeded in crows. These results suggest that pecking in pigeons predominantly involves feedforward control and that the movement is determined depending on the visual information available before the initiation of pecking. In contrast, the results from crows suggest that their pecking trajectories are corrected during the movement, supporting on-line visual control. Our findings provide the first evidence to suggest the on-line visual control of pecking in birds.

RevDate: 2020-03-23

Gallego-Abenza M, Loretto MC, T Bugnyar (2020)

Decision time modulates social foraging success in wild common ravens, Corvus corax.

Ethology : formerly Zeitschrift fur Tierpsychologie, 126(4):413-422.

Social foraging provides several benefits for individuals but also bears the potential costs of higher competition. In some species, such competition arises through kleptoparasitism, that is when an animal takes food which was caught or collected by a member of its social group. Except in the context of caching, few studies have investigated how individuals avoid kleptoparasitism, which could be based on physical strength/dominance but also cognitive skills. Here, we investigated the foraging success of wild common ravens, Corvus corax, experiencing high levels of kleptoparasitism from conspecifics when snatching food from the daily feedings of captive wild boars in a game park in the Austrian Alps. Success in keeping the food depended mainly on the individuals' age class and was positively correlated with the time to make a decision in whether to fly off with food or consume it on site. While the effect of age class suggests that dominant and/or experienced individuals are better in avoiding kleptoparasitism, the effect of decision time indicates that individuals benefit from applying cognition to such decision-making, independently of age class. We discuss our findings in the context of the ecological and social intelligence hypotheses referring to the development of cognitive abilities. We conclude that investigating which factors underline kleptoparasitism avoidance is a promising scenario to test specific predictions derived from these hypotheses.

RevDate: 2020-03-17
CmpDate: 2020-03-17

Schlötelburg A, Plekat A, Bellingrath-Kimura S, et al (2020)

Self-service traps inspected by avian and terrestrial predators as a management option for rodents.

Pest management science, 76(1):103-110.

BACKGROUND: Worldwide, serval rodent species are major pests in agricultural landscapes. A vole-specific tub-trap combining trapping and natural predators was developed to minimize the migration of rodents into agricultural crops. The trap was tested in enclosures in terms of its trapability of common voles (Microtus arvalis Pallas) and in the field regarding predator access and removal of voles, both in comparison to a commercially available self-service trap (standby-box).

RESULTS: The trapability of voles was equal for tub-traps and standby-boxes. The removal of voles occurred four times more often from tub-traps by a wider variety of predators (e.g. smaller terrestrial predators, birds of prey). Visits by predators were most likely if study sites were not surrounded by artificial surfaces (70% visit probability by terrestrial predators) or if they were in areas that were more than 25% (semi)natural (95% visit probability by avian predators). Furthermore, visits by avian predators increased with time and a learning effect could be demonstrated for magpies (Pica pica L.). From the first to the fifth day, the visit probability of magpies quadrupled.

CONCLUSIONS: Visits by predators decreased with increasing cover of artificial surfaces or decreasing cover of (semi)natural areas, proving the importance of (semi)natural areas in the agricultural landscape. Long-term trials with different baiting techniques and in landscapes characterized by organic farming should be conducted to ensure the regular removal of voles. The use of tub-traps that are frequently visited by predators could support crop protection, which might limit the use of rodenticide and the associated exposure risk of non-target wildlife. © 2019 Society of Chemical Industry.

RevDate: 2020-03-03
CmpDate: 2020-03-03

Gruber R, Schiestl M, Boeckle M, et al (2019)

New Caledonian Crows Use Mental Representations to Solve Metatool Problems.

Current biology : CB, 29(4):686-692.e3.

One of the mysteries of animal problem-solving is the extent to which animals mentally represent problems in their minds. Humans can imagine both the solution to a problem and the stages along the way [1-3], such as when we plan one or two moves ahead in chess. The extent to which other animals can do the same is far less clear [4-25]. Here, we presented New Caledonian crows with a series of metatool problems where each stage was out of sight of the others and the crows had to avoid either a distractor apparatus containing a non-functional tool or a non-functional apparatus containing a functional tool. Crows were able to mentally represent the sub-goals and goals of metatool problems: crows kept in mind the location and identities of out-of-sight tools and apparatuses while planning and performing a sequence of tool behaviors. This provides the first conclusive evidence that birds can plan several moves ahead while using tools.

RevDate: 2020-02-27
CmpDate: 2020-02-27

Brecht KF, Hage SR, Gavrilov N, et al (2019)

Volitional control of vocalizations in corvid songbirds.

PLoS biology, 17(8):e3000375 pii:PBIOLOGY-D-19-00036.

Songbirds are renowned for their acoustically elaborate songs. However, it is unclear whether songbirds can cognitively control their vocal output. Here, we show that crows, songbirds of the corvid family, can be trained to exert control over their vocalizations. In a detection task, three male carrion crows rapidly learned to emit vocalizations in response to a visual cue with no inherent meaning (go trials) and to withhold vocalizations in response to another cue (catch trials). Two of these crows were then trained on a go/nogo task, with the cue colors reversed, in addition to being rewarded for withholding vocalizations to yet another cue (nogo trials). Vocalizations in response to the detection of the go cue were temporally precise and highly reliable in all three crows. Crows also quickly learned to withhold vocal output in nogo trials, showing that vocalizations were not produced by an anticipation of a food reward in correct trials. The results demonstrate that corvids can volitionally control the release and onset of their vocalizations, suggesting that songbird vocalizations are under cognitive control and can be decoupled from affective states.

RevDate: 2020-02-25

Tringali A, Sherer DL, Cosgrove J, et al (2020)

Life history stage explains behavior in a social network before and during the early breeding season in a cooperatively breeding bird.

PeerJ, 8:e8302 pii:8302.

In species with stage-structured populations selection pressures may vary between different life history stages and result in stage-specific behaviors. We use life history stage to explain variation in the pre and early breeding season social behavior of a cooperatively breeding bird, the Florida scrub-jay (Aphelocoma coerulescens) using social network analysis. Life history stage explains much of the variation we observed in social network position. These differences are consistent with nearly 50 years of natural history observations and generally conform to a priori predictions about how individuals in different stages should behave to maximize their individual fitness. Where the results from the social network analysis differ from the a priori predictions suggest that social interactions between members of different groups are more important for breeders than previously thought. Our results emphasize the importance of accounting for life history stage in studies of individual social behavior.

RevDate: 2020-02-21
CmpDate: 2020-02-21

Rutz C, Hunt GR, JJH St Clair (2018)

Corvid Technologies: How Do New Caledonian Crows Get Their Tool Designs?.

Current biology : CB, 28(18):R1109-R1111.

Recent research shows that New Caledonian crows can incorporate information from researcher-made objects into objects they subsequently manufacture. This 'mental template matching' is one of several possible - mutually compatible - mechanisms for the cultural transmission of tool designs among wild crows.

RevDate: 2020-02-19
CmpDate: 2020-02-19

Taufique ST, Prabhat A, V Kumar (2019)

Light at night affects hippocampal and nidopallial cytoarchitecture: Implication for impairment of brain function in diurnal corvids.

Journal of experimental zoology. Part A, Ecological and integrative physiology, 331(2):149-156.

Our previous studies have shown that light at night (LAN) impaired cognitive performance and affected neurogenesis and neurochemistry in the cognition-associated brain regions, particularly the hippocampus (HP) and lateral caudal nidopallium (NCL) of Indian house crows (Corvus splendens). Here, we examined the cytoarchitecture and mapped out the morphology of neurons and glia-neuron density in HP and NCL regions of crows that were first entrained to 12-hr light (LL): 12-hr darkness (LD) and then exposed to the light regime in which 12-hr darkness was either replaced by daytime light (i.e., constant light, LL) or by dim light (i.e., dim light at night, dLAN), with controls continued on LD 12:12. Compared with LD, there was a significant decrease in the soma size, suggesting reduced neuronal plasticity without affecting the neuronal density of both HP and NCL of crows under LL and dLAN conditions. In parallel, we found a reduced number of glia cells and, hence, decreased glia-neuron ratio positively correlated with soma size in both, HP and NCL regions. These results for the first time demonstrate LAN-induced negative effects on the brain cytoarchitecture of a diurnal species and give insight for possible influence on the brain health and functions in animals including humans that might be inadvertently exposed to LAN in an emerging night-illuminated urban environment.

RevDate: 2020-02-13

Tryjanowski P, Hetman M, Czechowski P, et al (2020)

Birds Drinking Alcohol: Species and Relationship with People. A Review of Information from Scientific Literature and Social Media.

Animals : an open access journal from MDPI, 10(2): pii:ani10020270.

Ethanol is a natural by-product of the fermentation process of fruit sugars and is occasionally consumed by fruit-eating and tree sap drinking birds. Information on this form of alcohol consumption features in the scientific literature. However, as pets or as wild animals living close to humans in urban habitats, birds have increasing possibilities to consume alcohol from beverages, such as beer, wine or spirits. Some observations have been discussed in a light-hearted manner in mass media and social media, but without any generalization of why some bird species drink the beverages intentionally or unintentionally provided by humans. To check which species and in what circumstances birds drink alcohol and how this is evaluated by humans, we reviewed the scientific literature and analysed videos from YouTube. In total we found and analysed 8 scientific papers and 179 YouTube videos, from which we identified at least 55 species (in some cases not all birds were identified to species level), 11 in the scientific literature and 47 in videos. The distribution of these species over the avian phylogenetic tree suggests that the origin of this convergent behaviour is mainly by human influence. The two data sources differed in the species covered. Videos typically presented interactions of birds with human-provided alcoholic beverages, and were dominated by two groups of intelligent birds: parrots and corvids. The popularity of YouTube videos for a particular species was positively correlated with the general popularity of the species as measured by the number of hits (results listed) on Google. Human responses to the videos were generally very positive and we analysed how the responses were influenced by factors derived from viewing the videos. Moreover, YouTube videos also provide information on at least 47 new bird species not previously mentioned as using alcohol, and our results suggest that parrots in particular can be potentially good candidates for future restricted laboratory studies on the effect of ethanol on birds and their relationship with humans.

RevDate: 2020-01-18

Dutour M, AR Ridley (2020)

Females sing more often and at higher frequencies than males in Australian magpies.

Behavioural processes pii:S0376-6357(19)30305-5 [Epub ahead of print].

Birdsong is a particularly useful model for animal communication studies. However, current knowledge is derived mainly from the study of male song, and is therefore incomplete. Here, we investigated whether singing behaviour differs between sexes in the cooperatively breeding Western Australian magpie (Gymnorhina tibicen dorsalis). This subspecies lives in territorial groups, and in our population there is a female-biased sex ratio, which may lead to a high level of female-female competition for males. Observations of 94 magpies (54 females, 40 males) revealed that females sang more often than males. As bird song is a sexually multidimensional signal, we also studied amplitude and structure of the main territorial high-amplitude song in magpie; the carol. We found that females sing at the same amplitude as males, but that male and female carols exhibit differences in frequency. These results highlight the importance of studying female song and may change our perception regarding the evolution of sex-specific traits, given the primary focus on male singing as a sexually selected trait in the literature to date. The next step is to discover additional species in which females sing more than males in order to improve our currently incomplete understanding of the evolution of bird song.

RevDate: 2020-01-16

Vernouillet A, DM Kelly (2020)

Individual exploratory responses are not repeatable across time or context for four species of food-storing corvid.

Scientific reports, 10(1):394 pii:10.1038/s41598-019-56138-y.

Exploration is among one of the most studied of animal personality traits (i.e., individual-level behavioural responses repeatable across time and contexts). However, not all species show clear evidence of this personality trait, and this is particularly so for members of the Corvidae family. We assessed the exploratory behaviour of four food-caching corvid species: pinyon jays (Gymnorhinus cyanocephalus), Clark's nutcrackers (Nucifraga columbiana), California scrub jays (Aphelocoma californica), and black-billed magpies (Pica hudsonia). Contextual repeatability was assessed through examining behavioural measures during the Novel Environment task and the Novel Object task, whereas temporal repeatability was assessed by examining changes in these measures over repeated trials. Our results suggest that, for corvids, an individual's exploratory behaviour was not repeatable across contexts or over time. Hence, we found no evidence that exploration constitutes a personality trait for these species of corvid. We did find differences in exploratory behaviour, at a species level, that may be explained by relative reliance on cached food.

RevDate: 2020-01-15

Kövér L, Lengyel S, Takenaka M, et al (2019)

Why do zoos attract crows? A comparative study from Europe and Asia.

Ecology and evolution, 9(24):14465-14475 pii:ECE35881.

Crows have successfully colonized many cities, and urban zoos have been important in this process. To evaluate why zoos attract crows, we quantified crow numbers and behavior in three zoos in Europe (Debrecen, Edinburgh, Vienna) and one in Asia (Sapporo). Data were collected in 445 surveys over 297 days in summer 2014 and winter 2014-2015. We found that crow numbers were highest in Vienna, intermediate in Debrecen and Edinburgh and lowest in Sapporo, increased significantly from summer to winter (Debrecen, Edinburgh, Vienna), and from mornings to afternoons (Debrecen, Sapporo, Vienna), and were higher in sunny weather than in cloudy weather with precipitation and when visitor numbers were low (Debrecen, Vienna). The crows' use of natural food was highest in Vienna, intermediate in Edinburgh and Sapporo, and low in Debrecen. The use of anthropogenic food was high in Debrecen and Sapporo, where the availability of open grassy areas typically used by crows for natural foraging was low. In Sapporo, food availability was more limited than in other zoos, resulting in strong territoriality and few crows in summer, which decreased further in winter. Our study indicates that crows are primarily attracted to zoos by food availability and secondarily by breeding opportunities and that the relative importance of natural versus anthropogenic food sources may vary with zoo habitat structure. Our study draws attention to a previously overlooked role of zoos in urban biodiversity conservation. It may also provide useful information for the management of crow populations, if necessary, and for the planning of urban areas.

RevDate: 2020-01-14

Jiang S, Li Z, Cheng X, et al (2020)

The first pterosaur basihyal, shedding light on the evolution and function of pterosaur hyoid apparatuses.

PeerJ, 8:e8292 pii:8292.

The pterosaur is the first known vertebrate clade to achieve powered flight. Its hyoid apparatus shows a simplification similar to that of birds, although samples of the apparatus are rare, limiting the ability to make an accurate determination. In this study we reveal a new pterosaur specimen, including the first definite basihyal. Through the comparison of pterosaur hyoids, a trend has been discovered for the shortened hyoid relative to the length of the skull, indicating a diminished role of lingual retraction during the evolution of the pterosaur. The new material, possibly from a gallodactylid Gladocephaloideus, represents one of the least effective lingual retractions in all pterosaurs. Based on the structure of an elongated ceratobranchial and retroarticular process on mandibles, the function of the Y-shaped istiodactylid tongue bone is similar to those of scavenger crows rather than chameleons, which is consistent with the interpretation of the scavenging behavior of this taxon. More fossil samples are needed for further study on the function of other pterosaur hyoids.

RevDate: 2020-01-02

Abadi SH, Wacker DW, Newton JG, et al (2019)

Acoustic localization of crows in pre-roost aggregations.

The Journal of the Acoustical Society of America, 146(6):4664.

Crows are highly intelligent and social creatures. Each night during the non-breeding period, they gather on large pre-roost aggregations as they move towards their communal roost where they sleep. Crows make numerous and varied vocalizations on these pre-roost aggregations, but the purpose of these calls, and vocal communication in general, in these pre-roost aggregations is not fully understood. In this paper, an array of four microphones is used as a non-intrusive means to observe crow vocal behavior in pre-roost aggregations in the absence of human observers. By passively localizing animal vocalizations, the location of individuals can be monitored while simultaneously recording the acoustic structure and organization of their calls. Simulations and experiment are undertaken to study the performance of two time difference of arrival-based methods (hyperbolic location estimator and maximum likelihood estimator) for call localization. The effect of signal-to-noise ratio and uncertainty in measurement on the localization error is presented. By describing, modeling, and testing these techniques in this innovative context, the authors hope that researchers will employ the authors' approaches in future empirical studies to more fully understand crow vocal behavior.

RevDate: 2019-12-26

Ashton BJ, Thornton A, AR Ridley (2019)

Larger group sizes facilitate the emergence and spread of innovations in a group-living bird.

Animal behaviour, 158:1-7.

The benefits of group living have traditionally been attributed to risk dilution or the efficient exploitation of resources; individuals in social groups may therefore benefit from access to valuable information. If sociality facilitates access to information, then individuals in larger groups may be predicted to solve novel problems faster than individuals in smaller groups. Additionally, larger group sizes may facilitate the subsequent spread of innovations within animal groups, as has been proposed for human societies. We presented a novel foraging task (where a food reward could be accessed by pushing a self-shutting sliding door) to 16 groups of wild, cooperatively breeding Australian magpies, Cracticus tibicen dorsalis, ranging in size from two to 11 individuals. We found a nonlinear decline in the time taken for the innovative behaviour to emerge with increasing group size, and social information use facilitated the transmission of novel behaviour, with it spreading more quickly in larger than smaller groups. This study provides important evidence for a nonlinear relationship between group size and the emergence of innovation (and its subsequent transmission) in a wild population of animals. Further work investigating the scope and strength of group size-innovation relationships, and the mechanisms underpinning them, will help us understand the potential advantages of living in larger social groups.

RevDate: 2019-12-18

Ben-David A, Shamon H, Izhaki I, et al (2019)

Increased songbird nest depredation due to Aleppo pine (Pinus halepensis) encroachment in Mediterranean shrubland.

BMC ecology, 19(1):52 pii:10.1186/s12898-019-0270-8.

BACKGROUND: In recent decades, a decrease of passerine densities was documented in Mediterranean shrublands. At the same time, a widespread encroachment of Aleppo pines (Pinus halepensis) to Mediterranean shrubland occurred. Such changes in vegetation structure may affect passerine predator assemblage and densities, and in turn impact passerine densities. Depredation during the nesting season is an important factor to influence passerine population size. Understanding the effects of changes in vegetation structure (pine encroachment) on passerine nesting success is the main objective of this study. We do so by assessing the effects of Aleppo pine encroachment on Sardinian warbler (Sylvia melanocephala) nest depredation in Mediterranean shrublands. We examined direct and indirect predation pressures through a gradients of pine density, using four methods: (1) placing dummy nests; (2) acoustic monitoring of mobbing events; (3) direct observations on nest predation using cameras; and (4) observation of Eurasian jay (Garrulus glandarius) behaviour as indirect evidence of predation risk.

RESULTS: We found that Aleppo pine encroachment to Mediterranean shrublands increased nest predation by Eurasian jays. Nest predation was highest in mixed shrubland and pines. These areas are suitable for warblers but had high occurrence rate of Eurasian jays.

CONCLUSIONS: Encroaching pines directly increase activity of Eurasian jays in shrubland habitats, which reduced the nesting success of Sardinian warblers. These findings are supported by multiple methodologies, illustrating different predation pressures along a gradient of pine densities in natural shrublands. Management of Aleppo pine seedlings and removal of unwanted trees in natural shrubland might mitigate arrival and expansion of predators and decrease the predation pressure on passerine nests.

RevDate: 2019-12-17
CmpDate: 2019-12-12

Maron JL, Agrawal AA, DW Schemske (2019)

Plant-herbivore coevolution and plant speciation.

Ecology, 100(7):e02704.

More than five decades ago, Ehrlich and Raven proposed a revolutionary idea-that the evolution of novel plant defense could spur adaptive radiation in plants. Despite motivating much work on plant-herbivore coevolution and defense theory, Ehrlich and Raven never proposed a mechanism for their "escape and radiate" model. Recent intriguing mechanisms proposed by Marquis et al. include sympatric divergence, pleiotropic effects of plant defense traits on reproductive isolation, and strong postzygotic isolation, but these may not be general features of herbivore-mediated speciation. An alternate view is that herbivores may impose strong divergent selection on defenses in allopatric plant populations, with plant-herbivore coevolution driving local adaptation resulting in plant speciation. Building on these ideas, we propose three scenarios that consider the role of herbivores in plant speciation. These include (1) vicariance, subsequent coevolution within populations and adaptive divergence between geographically isolated populations, (2) colonization of a new habitat lacking effective herbivores followed by loss of defense and then re-evolution and coevolution of defense in response to novel herbivores, and (3) evolution of a new defense followed by range expansion, vicariance, and coevolution. We discuss the general role of coevolution in plant speciation and consider outstanding issues related to understanding: (1) the mechanisms behind cospeciation of plants and insects, (2) geographic variation in defense phenotypes, (3) how defensive traits and geography map on plant phylogenies, and (4) the role of herbivores in driving character displacement in defense phenotypes of related species in sympatry.

RevDate: 2019-12-17
CmpDate: 2019-12-17

Bugnyar T (2019)

Tool Use: New Caledonian Crows Engage in Mental Planning.

Current biology : CB, 29(6):R200-R202.

New Caledonian crows are able to flexibly use different tools in a sequence to retrieve food, whereby each step is out-of-sight of the others. Mental planning is thus not a human-specific trait.

RevDate: 2019-12-17
CmpDate: 2019-12-11

Bayern AMPV, Danel S, Auersperg AMI, et al (2018)

Compound tool construction by New Caledonian crows.

Scientific reports, 8(1):15676.

The construction of novel compound tools through assemblage of otherwise non-functional elements involves anticipation of the affordances of the tools to be built. Except for few observations in captive great apes, compound tool construction is unknown outside humans, and tool innovation appears late in human ontogeny. We report that habitually tool-using New Caledonian crows (Corvus moneduloides) can combine objects to construct novel compound tools. We presented 8 naïve crows with combinable elements too short to retrieve food targets. Four crows spontaneously combined elements to make functional tools, and did so conditionally on the position of food. One of them made 3- and 4-piece tools when required. In humans, individual innovation in compound tool construction is often claimed to be evolutionarily and mechanistically related to planning, complex task coordination, executive control, and even language. Our results are not accountable by direct reinforcement learning but corroborate that these crows possess highly flexible abilities that allow them to solve novel problems rapidly. The underlying cognitive processes however remain opaque for now. They probably include the species' typical propensity to use tools, their ability to judge affordances that make some objects usable as tools, and an ability to innovate perhaps through virtual, cognitive simulations.

RevDate: 2019-12-10
CmpDate: 2017-04-28

Kazemeini T, JS Fadardi (2016)

Executive Function: Comparing Bilingual and Monolingual Iranian University Students.

Journal of psycholinguistic research, 45(6):1315-1326.

The study aimed to examine whether Kurdish-Persian early Bilingual university students (EBL) and Persian Monolingual university students (ML) differ on tasks of executive function (EF). Thirty male EBL and 30 male ML students from Ferdowsi University of Mashhad completed a Persian Stroop Color-Word task (SCWT), Backward Digit Span Test (BDST), Raven Standard Progressive Matrices, and a demographic questionnaire. The results of an analysis of variance showed EBL students responded faster on the SCWT compared with ML students, suggesting an inhibition advantage for EBL students. Moreover, mean scores of BDST showed better performance of EBL students in working memory than ML students. These results provided evidence of advantaged EF among EBL and were consistent with the possibility that individuals who began speaking a second language (L2) earlier in childhood have greater advantages, due either to effects of acquiring an L2 earlier or to a longer duration of bilingual experience.

RevDate: 2019-12-12

Tätte K, Møller AP, R Mänd (2019)

Corvids exhibit dynamic risk assessment during escape.

Behavioural processes pii:S0376-6357(19)30346-8 [Epub ahead of print].

It is widely accepted that stationary prey are able to carefully assess the risk levels associated with an approaching predator to make informative decisions on when to escape. However, little is known about subsequent decision-making process. We set out to compare whether escape durations of three species of corvids differ depending on how a human observer (in the role of a predator) behaves after the escape has begun. When birds were being followed during escape, escape durations were the longest, escape trajectory was modified the most during escape, and a larger proportion of individuals changed from terrestrial to aerial escape strategy compared to observations where birds were not followed. Mean horizontal escape angle of ca 120º was also a potential indication that monitoring the threat is taken into account when deciding on the escape trajectory. While there were some differences between the behaviour of these three closely related species, the general patterns supported the notion that birds dynamically assess risk during escape to find an optimal balance between getting caught and spending too much time and energy on escaping. Further research using different predator-prey combinations or making comparisons between habitats could help understand the generality of our results.

RevDate: 2019-11-26

Klump BC (2019)

Of crows and tools.

Science (New York, N.Y.), 366(6468):965.

RevDate: 2019-11-29

Lambert CT, Sewall KB, LM Guillette (2019)

Questioning the developmental effects of group size on cognitive abilities.

Learning & behavior, 47(4):280-283.

Australian magpies living in larger social groups learned quicker and made fewer errors across four cognitive tasks compared with birds living in smaller social groups, and this pattern may be driven by a developmental effect associated with the cognitive demands of living in larger groups. While Smulders (2018, Learning and Behavior, 1-2, doi:10.3758/s13420-018-0335-0) questioned whether this group size-cognitive performance pattern was driven by motivation rather than cognitive abilities, we question whether there is truly evidence of a developmental effect and whether the relationship between group size and cognitive performance can be explained in other ways. We highlight potential alternative explanations for the relationship between group size and cognitive performance and highlight some of the theoretical issues underlying the developmental effects of group size on cognitive abilities.

RevDate: 2019-11-21

Ling H, Mclvor GE, Westley J, et al (2019)

Behavioural plasticity and the transition to order in jackdaw flocks.

Nature communications, 10(1):5174.

Collective behaviour is typically thought to arise from individuals following fixed interaction rules. The possibility that interaction rules may change under different circumstances has thus only rarely been investigated. Here we show that local interactions in flocks of wild jackdaws (Corvus monedula) vary drastically in different contexts, leading to distinct group-level properties. Jackdaws interact with a fixed number of neighbours (topological interactions) when traveling to roosts, but coordinate with neighbours based on spatial distance (metric interactions) during collective anti-predator mobbing events. Consequently, mobbing flocks exhibit a dramatic transition from disordered aggregations to ordered motion as group density increases, unlike transit flocks where order is independent of density. The relationship between group density and group order during this transition agrees well with a generic self-propelled particle model. Our results demonstrate plasticity in local interaction rules and have implications for both natural and artificial collective systems.

RevDate: 2019-11-26

Coomes JR, McIvor GE, A Thornton (2019)

Correction to 'Evidence for individual discrimination and numerical assessment in collective antipredator behaviour in wild jackdaws (Corvus monedula)'.

Biology letters, 15(11):20190740.

RevDate: 2019-11-14

Holtmann B, Buskas J, Steele M, et al (2019)

Dominance relationships and coalitionary aggression against conspecifics in female carrion crows.

Scientific reports, 9(1):15922.

Cooperation is a prevailing feature of many animal systems. Coalitionary aggression, where a group of individuals engages in coordinated behaviour to the detriment of conspecific targets, is a form of cooperation involving complex social interactions. To date, evidence has been dominated by studies in humans and other primates with a clear bias towards studies of male-male coalitions. We here characterize coalitionary aggression behaviour in a group of female carrion crows consisting of recruitment, coordinated chase, and attack. The individual of highest social rank liaised with the second most dominant individual to engage in coordinated chase and attack of a lower ranked crow on several occasions. Despite active intervention by the third most highly ranked individual opposing the offenders, the attack finally resulted in the death of the victim. All individuals were unrelated, of the same sex, and naïve to the behaviour excluding kinship, reproduction, and social learning as possible drivers. Instead, the coalition may reflect a strategy of the dominant individual to secure long-term social benefits. Overall, the study provides evidence that members of the crow family engage in coordinated alliances directed against conspecifics as a possible means to manipulate their social environment.

RevDate: 2019-11-14

Ling H, Mclvor GE, Westley J, et al (2019)

Collective turns in jackdaw flocks: kinematics and information transfer.

Journal of the Royal Society, Interface, 16(159):20190450.

The rapid, cohesive turns of bird flocks are one of the most vivid examples of collective behaviour in nature, and have attracted much research. Three-dimensional imaging techniques now allow us to characterize the kinematics of turning and their group-level consequences in precise detail. We measured the kinematics of flocks of wild jackdaws executing collective turns in two contexts: during transit to roosts and anti-predator mobbing. All flocks reduced their speed during turns, probably because of constraints on individual flight capability. Turn rates increased with the angle of the turn so that the time to complete turns remained constant. We also find that context may alter where turns are initiated in the flocks: for transit flocks in the absence of predators, initiators were located throughout the flocks, but for mobbing flocks with a fixed ground-based predator, they were always located at the front. Moreover, in some transit flocks, initiators were far apart from each other, potentially because of the existence of subgroups and variation in individual interaction ranges. Finally, we find that as the group size increased the information transfer speed initially increased, but rapidly saturated to a constant value. Our results highlight previously unrecognized complexity in turning kinematics and information transfer in social animals.

RevDate: 2019-10-16

El-Sayed AK, S Hassan (2019)

Gross morphological features of the air sacs of the hooded crow (Corvus cornix).

Anatomia, histologia, embryologia [Epub ahead of print].

Air sacs are considered to be one of the controlling factors of bird behaviour and habits in addition to their roles in ventilation, regulating body temperature, swimming and flight. As a scavenger and an omnivorous flight bird, air sacs of the hooded crow were the focus of this study. Eight healthy, adult hooded crows were used to examine the morphological characteristics of the air sacs, which were examined grossly and with latex and cast preparations. In general, the morphological overview of the hooded crow air sacs is similar to other avian species. We observed nine air sacs; four paired sacs (cervical, cranial thoracic, caudal thoracic and abdominal air sacs) and one unpaired sac; the clavicular air sac. The cervical air sac communicated to the lung through the medioventral bronchus and had three diverticula; intermuscular, subscapular and subcutaneous. The clavicular air sac communicated with lung through the medioventral bronchus and had subscapular, axillary, humeral, subpectoral and sternal diverticula. The cranial and caudal thoracic air sacs were communicated with lung through the lateroventral bronchi and the both sacs did not have any diverticula. The abdominal air sacs were posterior to the caudal thoracic air sacs. The left abdominal sac was the largest air sac. The right and left abdominal sacs gave off branches to diverticula that pneumatized synsacrum. The abdominal air sacs gave off femoral diverticula behind the hip joint as well as perirenal diverticula.

RevDate: 2019-10-07

Vanhooland LC, Bugnyar T, JJM Massen (2019)

Crows (Corvus corone ssp.) check contingency in a mirror yet fail the mirror-mark test.

Journal of comparative psychology (Washington, D.C. : 1983) pii:2019-59593-001 [Epub ahead of print].

Mirror reflections can elicit various behavioral responses ranging from social behavior, which suggests that an animal treats its own reflection as a conspecific, to mirror-guided self-directed behaviors, which appears to be an indication for mirror self-recognition (MSR). MSR is scarcely spread in the animal kingdom. Until recently, only great apes, dolphins, and elephants had successfully passed this test. The range of convergence was, however, expanded by an avian species, the Eurasian magpie (Pica pica). Efforts to find MSR in other corvid species have so far failed, and with only a few studies conducted, the cause of these discrepancies is difficult to identify. In the present study, we examined the responses to mirrors and the ability of MSR in hitherto untested species: the carrion and hooded crows (Corvus corone ssp.). These crows showed a pronounced and lasting interest in the mirror; unlike many species, they did not exhibit social behaviors on their first encounters but immediately started investigating the mirror. Some crows showed contingent behaviors in front of the mirror, but none of the crows showed significant mirror-guided self-directed behaviors nor mark-directed behavior during the subsequent mark test. This lack of mark-directed behavior could not be explained by a lack of interest in the mirror nor in the mark. These findings could indicate that crows lack a concept of self, or the need for other means of investigating self-recognition and self-awareness in avian species. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

RevDate: 2019-12-10

Coomes JR, McIvor GE, A Thornton (2019)

Evidence for individual discrimination and numerical assessment in collective antipredator behaviour in wild jackdaws (Corvus monedula).

Biology letters, 15(10):20190380.

Collective responses to threats occur throughout the animal kingdom but little is known about the cognitive processes underpinning them. Antipredator mobbing is one such response. Approaching a predator may be highly risky, but the individual risk declines and the likelihood of repelling the predator increases in larger mobbing groups. The ability to appraise the number of conspecifics involved in a mobbing event could therefore facilitate strategic decisions about whether to join. Mobs are commonly initiated by recruitment calls, which may provide valuable information to guide decision-making. We tested whether the number of wild jackdaws responding to recruitment calls was influenced by the number of callers. As predicted, playbacks simulating three or five callers tended to recruit more individuals than playbacks of one caller. Recruitment also substantially increased if recruits themselves produced calls. These results suggest that jackdaws use individual vocal discrimination to assess the number of conspecifics involved in initiating mobbing events, and use this information to guide their responses. Our results show support for the use of numerical assessment in antipredator mobbing responses and highlight the need for a greater understanding of the cognitive processes involved in collective behaviour.

RevDate: 2019-10-23

Forti LR, Haddad CFB, Leite F, et al (2019)

Notes on vocalizations of Brazilian amphibians IV: advertisement calls of 20 Atlantic Forest frog species.

PeerJ, 7:e7612.

Bioacoustics is a powerful tool used for anuran species diagnoses, given that advertisement calls are signals related to specific recognition and mate attraction. Thus, call descriptions can support species taxonomy. In spite of that, call descriptions are lacking for many species, delaying advances in biodiversity research. Here, we describe the advertisement calls of 20 anuran species from the Brazilian Atlantic Forest. We accessed 50 digital recordings deposited in the Fonoteca Neotropical Jacques Vielliard. Acoustic analyses were carried out in the software Raven pro 1.5. We provide a general comparison of call structure among species inside taxonomic groups and genera. The vocalizations described here belong to poorly known species, which are representatives of six families: Brachycephalidae, Bufonidae, Ceratophryidae, Cycloramphidae, Hylidae, and Phyllomedusidae. Despite this, still there are 163 species of anurans from Atlantic Forest with calls not formally described. Our work represents an important step in providing data for a taxonomic perspective and improving the knowledge of the Atlantic Forest anuran diversity.

RevDate: 2019-10-26

Blasco R, Rosell J, Sánchez-Marco A, et al (2019)

Feathers and food: Human-bird interactions at Middle Pleistocene Qesem Cave, Israel.

Journal of human evolution, 136:102653.

The presence of fast-moving small game in the Paleolithic archaeological faunal record has long been considered a key variable to assess fundamental aspects of human behavior and subsistence. Birds occupy a prominent place in this debate not only due to their small size and to the difficulties in capturing them (essentially due to their ability to fly and their elusiveness), but also due to their possible role in the symbolic array in regard to non-nutritional elements (feathers, talons, etc.) and as reflectors of complex human-world relationships. In this study, we attempt to contribute to this topic by presenting taphonomical data of bird specimens from Qesem Cave (Israel), dated between 420 and 200 ka. Human-induced damage, including cut marks, peeling and human gnawing, has been identified on wing bones of Cygnus sp., Columba sp., Corvus ruficollis and Sturnus sp. Our evidence suggests that avian exploitation was not limited to food only-either to complement the human diet or as occasional food item-but also presumably for the use of feathers. While the consumption of birds as a dietary source seems to be evident as early as the Early Pleistocene, the non-alimentary use of inedible elements, such as feathers and talons, appears to be a practice from the Middle Paleolithic onwards. We argue that the combined nutritional and symbolic use of birds is one characteristic of the new mode of adaptation practiced already by the late Lower Paleolithic Acheulo-Yabrudian hominins in the Levant starting 400 ka. The Qesem findings point to the possible emergence of new cognitive and behavioral skills, which are followed in later periods in the Old World. Finally, we discuss the possible ontological and cosmological significance of human-bird interactions to illuminate our hypothesis regarding the emergence of a new perception of human relationships with the world as an integral part of the new Acheulo-Yabrudian mode of adaptation.

RevDate: 2019-09-13

Shekhawat S, A Saxena (2019)

Development and applications of an intelligent crow search algorithm based on opposition based learning.

ISA transactions pii:S0019-0578(19)30419-7 [Epub ahead of print].

Metaheuristics are proven beneficial tools for solving complex, hard optimization problems. Recently, a plethora of work has been reported on bio inspired optimization algorithms. These algorithms are mimicry of behavior of animals, plants and processes into mathematical paradigms. With these developments, a new entrant in this group is Crow Search Algorithm (CSA). CSA is based on the strategic behavior of crows while searching food, thievery and chasing behavior. This algorithm sometimes suffers with local minima stagnation and unbalance exploration and exploitation phases. To overcome this problem, a cosine function is proposed first, to accelerate the exploration and retard the exploitation process with due course of the iterative process. Secondly the opposition based learning concept is incorporated for enhancing the exploration virtue of CSA. The evolved variant with the inculcation of these two concepts is named as Intelligent Crow Search Algorithm (ICSA). The algorithm is benchmarked on two benchmark function sets, one is the set of 23 standard test functions and another is set of latest benchmark function CEC-2017. Further, the applicability of this variant is tested over structural design problem, frequency wave synthesis problem and Model Order Reduction (MOR). Results reveal that ICSA exhibits competitive performance on benchmarks and real applications when compared with some contemporary optimizers.

RevDate: 2019-09-29

Vonk J (2019)

Emotional contagion or sensitivity to behavior in ravens?.

Proceedings of the National Academy of Sciences of the United States of America, 116(37):18168.

RevDate: 2019-08-20

McCoy DE, Schiestl M, Neilands P, et al (2019)

New Caledonian Crows Behave Optimistically after Using Tools.

Current biology : CB, 29(16):2737-2742.e3.

Are complex, species-specific behaviors in animals reinforced by material reward alone or do they also induce positive emotions? Many adaptive human behaviors are intrinsically motivated: they not only improve our material outcomes, but improve our affect as well [1-8]. Work to date on animal optimism, as an indicator of positive affect, has generally focused on how animals react to change in their circumstances, such as when their environment is enriched [9-14] or they are manipulated by humans [15-23], rather than whether complex actions improve emotional state. Here, we show that wild New Caledonian crows are optimistic after tool use, a complex, species-specific behavior. We further demonstrate that this finding cannot be explained by the crows needing to put more effort into gaining food. Our findings therefore raise the possibility that intrinsic motivation (enjoyment) may be a fundamental proximate cause in the evolution of tool use and other complex behaviors. VIDEO ABSTRACT.

RevDate: 2019-07-22

Lazareva OF, Gould K, Linert J, et al (2019)

Smaller on the left? Flexible association between space and magnitude in pigeons (Columba livia) and blue jays (Cyanocitta cristata).

Journal of comparative psychology (Washington, D.C. : 1983) pii:2019-41901-001 [Epub ahead of print].

Humans and other apes represent magnitudes spatially, demonstrated by their responding faster and more accurately to one side of space when presented with small quantities and to the other side of space when presented with large quantities. This representation is flexible and shows substantial variability between cultural groups in humans and between and within individuals in great apes. In contrast, recent findings suggest that chicks show a spatial representation of magnitude that is highly lateralized and inflexible, implying a qualitatively different underlying representation than in primates. Using methods similar to those used with great apes and humans, we trained adult domestic pigeons (Columba livia) and blue jays (Cyanocitta cristata) to select the smaller (or larger) of two nonadjacent quantity arrays; later, this task was reversed. At test, birds were presented with novel probe pairs consisting of adjacent quantity pairs (e.g., 2 vs. 3). Both species showed robust evidence for a flexible spatial representation of magnitude with considerable individual variability in the orientation of this representation. These results are not consistent with an inflexible, lateralized, left-to-right representation of magnitude in birds, but are consistent with the flexible spatial representation of magnitude observed in apes and humans. We conclude that the tendency to organize quantities spatially may be a fundamental and evolutionarily ancient feature of cognition that is widespread among vertebrates. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

RevDate: 2019-07-04

Vonk J (2019)

Sticks and stones: Associative learning alone?.

Learning & behavior pii:10.3758/s13420-019-00387-4 [Epub ahead of print].

Gruber et al. (Current Biology, 29, 686-692, 2019) report that New Caledonian crows engage in mental representation to solve a problem involving a tool. Although the crows' success is impressive, an associative account of their behavior calls into question the extent to which the data reflect representation of future states.

RevDate: 2019-07-30

Ling H, Mclvor GE, van der Vaart K, et al (2019)

Local interactions and their group-level consequences in flocking jackdaws.

Proceedings. Biological sciences, 286(1906):20190865.

As one of nature's most striking examples of collective behaviour, bird flocks have attracted extensive research. However, we still lack an understanding of the attractive and repulsive forces that govern interactions between individuals within flocks and how these forces influence neighbours' relative positions and ultimately determine the shape of flocks. We address these issues by analysing the three-dimensional movements of wild jackdaws (Corvus monedula) in flocks containing 2-338 individuals. We quantify the social interaction forces in large, airborne flocks and find that these forces are highly anisotropic. The long-range attraction in the direction perpendicular to the movement direction is stronger than that along it, and the short-range repulsion is generated mainly by turning rather than changing speed. We explain this phenomenon by considering wingbeat frequency and the change in kinetic and gravitational potential energy during flight, and find that changing the direction of movement is less energetically costly than adjusting speed for birds. Furthermore, our data show that collision avoidance by turning can alter local neighbour distributions and ultimately change the group shape. Our results illustrate the macroscopic consequences of anisotropic interaction forces in bird flocks, and help to draw links between group structure, local interactions and the biophysics of animal locomotion.

RevDate: 2019-10-12

Federspiel IG, Boeckle M, von Bayern AMP, et al (2019)

Exploring individual and social learning in jackdaws (Corvus monedula).

Learning & behavior, 47(3):258-270.

Information about novel environments or foods can be gathered via individual or social learning. Whereas individual learning is assumed to be more costly and less effective than social learning, it also yields more detailed information. Juveniles are often found to be more explorative than adults. Still under the protection of their parents, this allows them to sample their environment in preparation for later in life. We tested individual and social learning in jackdaws (Corvus monedula) of different age groups in a semi-natural group setting. Juvenile and adult jackdaws differed in their learning propensity. Juveniles spent more time at the test apparatus, were more explorative, and caused the apparatus to open. Almost all the openings at the apparatus matched the demonstrated method. As more observers became available, the juveniles could observe each other. Individuals preferentially watched successful conspecifics and those they could scrounge food from. Lower-ranking individuals tended to watch higher ranking ones; higher ranking individuals preferentially watched conspecifics of similar rank. The control group did not manipulate the apparatus. Due to the lack of this baseline, it was difficult to determine for certain whether the opening technique was acquired via individual or social learning. We conclude that if social learning played a role, the underlying mechanism was most likely local or stimulus enhancement. It is, however, more parsimonious to assume that juveniles were more explorative than adults, and that their opening technique was potentially easier to acquire than the one demonstrated to adults.

RevDate: 2019-11-20

Adriaense JEC, Martin JS, Schiestl M, et al (2019)

Negative emotional contagion and cognitive bias in common ravens (Corvus corax).

Proceedings of the National Academy of Sciences of the United States of America, 116(23):11547-11552.

Emotional contagion is described as an emotional state matching between subjects, and has been suggested to facilitate communication and coordination in complex social groups. Empirical studies typically focus on the measurement of behavioral contagion and emotional arousal, yet, while highly important, such an approach often disregards an additional evaluation of the underlying emotional valence. Here, we studied emotional contagion in ravens by applying a judgment bias paradigm to assess emotional valence. We experimentally manipulated positive and negative affective states in demonstrator ravens, to which they responded with increased attention and interest in the positive condition, as well as increased redirected behavior and a left-eye lateralization in the negative condition. During this emotion manipulation, another raven observed the demonstrator's behavior, and we used a bias paradigm to assess the emotional valence of the observer to determine whether emotional contagion had occurred. Observers showed a pessimism bias toward the presented ambiguous stimuli after perceiving demonstrators in a negative state, indicating emotional state matching based on the demonstrators' behavioral cues and confirming our prediction of negative emotional contagion. We did not find any judgment bias in the positive condition. This result critically expands upon observational studies of contagious play in ravens, providing experimental evidence that emotional contagion is present not only in mammalian but also in avian species. Importantly, this finding also acts as a stepping stone toward understanding the evolution of empathy, as this essential social skill may have emerged across these taxa in response to similar socioecological challenges.

RevDate: 2019-11-19

Miller R, Boeckle M, Jelbert SA, et al (2019)

Self-control in crows, parrots and nonhuman primates.

Wiley interdisciplinary reviews. Cognitive science, 10(6):e1504.

Self-control is critical for both humans and nonhuman animals because it underlies complex cognitive abilities, such as decision-making and future planning, enabling goal-directed behavior. For instance, it is positively associated with social competence and life success measures in humans. We present the first review of delay of gratification as a measure of self-control in nonhuman primates, corvids (crow family) and psittacines (parrot order): disparate groups that show comparable advanced cognitive abilities and similar socio-ecological factors. We compare delay of gratification performance and identify key issues and outstanding areas for future research, including finding the best measures and drivers of delayed gratification. Our review therefore contributes to our understanding of both delayed gratification as a measure of self-control and of complex cognition in animals. This article is categorized under: Cognitive Biology > Evolutionary Roots of Cognition Psychology > Comparative Psychology.

RevDate: 2019-10-11
CmpDate: 2019-10-11

Ling H, Mclvor GE, van der Vaart K, et al (2019)

Costs and benefits of social relationships in the collective motion of bird flocks.

Nature ecology & evolution, 3(6):943-948.

Current understanding of collective behaviour in nature is based largely on models that assume that identical agents obey the same interaction rules, but in reality interactions may be influenced by social relationships among group members. Here, we show that social relationships transform local interactions and collective dynamics. We tracked individuals' three-dimensional trajectories within flocks of jackdaws, a species that forms lifelong pair-bonds. Reflecting this social system, we find that flocks contain internal sub-structure, with discrete pairs of individuals tied together by spring-like effective forces. Within flocks, paired birds interacted with fewer neighbours than unpaired birds and flapped their wings more slowly, which may result in energy savings. However, flocks with more paired birds had shorter correlation lengths, which is likely to inhibit efficient information transfer through the flock. Similar changes to group properties emerge naturally from a generic self-propelled particle model. These results reveal a critical tension between individual- and group-level benefits during collective behaviour in species with differentiated social relationships, and have major evolutionary and cognitive implications.

RevDate: 2019-11-20

Jelbert SA, Miller R, Schiestl M, et al (2019)

New Caledonian crows infer the weight of objects from observing their movements in a breeze.

Proceedings. Biological sciences, 286(1894):20182332.

Humans use a variety of cues to infer an object's weight, including how easily objects can be moved. For example, if we observe an object being blown down the street by the wind, we can infer that it is light. Here, we tested whether New Caledonian crows make this type of inference. After training that only one type of object (either light or heavy) was rewarded when dropped into a food dispenser, birds observed pairs of novel objects (one light and one heavy) suspended from strings in front of an electric fan. The fan was either on-creating a breeze which buffeted the light, but not the heavy, object-or off, leaving both objects stationary. In subsequent test trials, birds could drop one, or both, of the novel objects into the food dispenser. Despite having no opportunity to handle these objects prior to testing, birds touched the correct object (light or heavy) first in 73% of experimental trials, and were at chance in control trials. Our results suggest that birds used pre-existing knowledge about the behaviour exhibited by differently weighted objects in the wind to infer their weight, using this information to guide their choices.

RevDate: 2019-10-23
CmpDate: 2019-10-23

Klump BC, Cantat M, C Rutz (2019)

Raw-material selectivity in hook-tool-crafting New Caledonian crows.

Biology letters, 15(2):20180836.

Animals that manufacture foraging tools face the challenge of identifying suitable raw materials among a multitude of options. New Caledonian crows exhibit strong population-specific material preferences for the manufacture of hooked stick tools, but it is unknown how they identify their favourite plants. We investigated experimentally whether crows pay attention to the stems of plants (from which the tools are made) and/or their leaves (which are usually discarded during manufacture but may enable rapid and reliable species identification at a distance). Subjects were highly selective in choice trials with multiple plant species. Two additional treatments with experimental leaf-stem combinations revealed that birds can identify their preferred plant species by its stems alone, and possibly also its leaves. These findings encourage future experiments that investigate whether New Caledonian crows attend to features of the stem that are required for the production of efficient hooked stick tools. Our study provides one of the most detailed assessments to date of how non-human animals identify raw materials for tool manufacture.

RevDate: 2019-11-20

Boucherie PH, Loretto MC, Massen JJM, et al (2019)

What constitutes "social complexity" and "social intelligence" in birds? Lessons from ravens.

Behavioral ecology and sociobiology, 73(1):12.

In the last decades, the assumption that complex social life is cognitively challenging, and thus can drive mental evolution, has received much support from empirical studies in nonhuman primates. While extending the scope to other mammals and birds, different views have been adopted on what constitutes social complexity and which specific cognitive skills are selected for. Notably, many avian species form "open" groups as non-breeders (i.e., seasonally and before sexual maturity) that have been largely ignored as potential sources of social complexity. Reviewing 30 years of research on ravens, we illustrate the socio-ecological conditions faced by these birds as non-breeders and discuss how these relate to their socio-cognitive skills. We argue that the non-breeding period is key to understand raven social life and, to a larger extent, avian social life in general. We furthermore emphasize how the combination of the large-scale perspective (defining social system components: e.g., social organization, mating system) and the individual-scale perspective on social systems allows to better capture the complete set of social challenges experienced by individuals throughout their life, ultimately resulting on a more comprehensive understanding of species' social complexity.

RevDate: 2019-12-02
CmpDate: 2019-12-02

Matsui H, EI Izawa (2019)

Control of bill-grasping aperture with varying food size in crows.

Neuroreport, 30(7):522-525.

Grasping movement in primates is known to be a visually guided behavior and the aperture of hand opening is adjusted to the target size on the basis of visual information. The analogous behavior can be found in birds, called 'pecking', consisting of head-reaching and bill-grasping. Bill-grasping has been investigated mainly in pigeons and an aperture adjustment as seen in primates has been reported. This study focused on kinematics of pecking in crows, known to possess dexterous visuomotor skills, to examine whether crows adjust the grasping aperture to food diameter with a kinematic mechanism similar to that in pigeons. The pecking at a small piece of food was video recorded to analyze the grasping aperture. The results showed that the grasping aperture was proportional to food diameter. Kinematic analysis showed that the aperture adjustment was mediated by grasping velocity and grasping duration, which is consistent with the findings of previous research on pecking in pigeons. However, the relative contribution of grasping velocity was much higher than that of grasping duration. Our findings suggest the different sensorimotor mechanisms to control bill-grasping between the avian species with different foraging ecology.

RevDate: 2019-11-20

Policht R, Hart V, Goncharov D, et al (2019)

Vocal recognition of a nest-predator in black grouse.

PeerJ, 7:e6533 pii:6533.

Corvids count among the important predators of bird nests. They are vocal animals and one can expect that birds threatened by their predation, such as black grouse, are sensitive to and recognize their calls. Within the framework of field studies, we noticed that adult black grouse were alerted by raven calls during periods outside the breeding season. Since black grouse are large, extremely precocial birds, this reaction can hardly be explained by sensitization specifically to the threat of nest predation by ravens. This surprising observation prompted us to study the phenomenon more systematically. According to our knowledge, the response of birds to corvid vocalization has been studied in altricial birds only. We tested whether the black grouse distinguishes and responds specifically to playback calls of the common raven. Black grouse recognized raven calls and were alerted, displaying typical neck stretching, followed by head scanning, and eventual escape. Surprisingly, males tended to react faster and exhibited a longer duration of vigilance behavior compared to females. Although raven calls are recognized by adult black grouse out of the nesting period, they are not directly endangered by the raven. We speculate that the responsiveness of adult grouse to raven calls might be explained as a learned response in juveniles from nesting hens that is then preserved in adults, or by a known association between the raven and the red fox. In that case, calls of the raven would be rather interpreted as a warning signal of probable proximity of the red fox.

RevDate: 2019-04-08
CmpDate: 2019-04-08

Gutiérrez-López R, Martínez-de la Puente J, Gangoso L, et al (2019)

Effects of host sex, body mass and infection by avian Plasmodium on the biting rate of two mosquito species with different feeding preferences.

Parasites & vectors, 12(1):87 pii:10.1186/s13071-019-3342-x.

BACKGROUND: The transmission of mosquito-borne pathogens is strongly influenced by the contact rates between mosquitoes and susceptible hosts. The biting rates of mosquitoes depend on different factors including the mosquito species and host-related traits (i.e. odour, heat and behaviour). However, host characteristics potentially affecting intraspecific differences in the biting rate of mosquitoes are poorly known. Here, we assessed the impact of three host-related traits on the biting rate of two mosquito species with different feeding preferences: the ornithophilic Culex pipiens and the mammophilic Ochlerotatus (Aedes) caspius. Seventy-two jackdaws Corvus monedula and 101 house sparrows Passer domesticus were individually exposed to mosquito bites to test the effect of host sex, body mass and infection status by the avian malaria parasite Plasmodium on biting rates.

RESULTS: Ochlerotatus caspius showed significantly higher biting rates than Cx. pipiens on jackdaws, but non-significant differences were found on house sparrows. In addition, more Oc. caspius fed on female than on male jackdaws, while no differences were found for Cx. pipiens. The biting rate of mosquitoes on house sparrows increased through the year. The bird infection status and body mass of both avian hosts were not related to the biting rate of both mosquito species.

CONCLUSIONS: Host sex was the only host-related trait potentially affecting the biting rate of mosquitoes, although its effect may differ between mosquito and host species.

RevDate: 2019-11-20

Shimmura T, Tamura M, Ohashi S, et al (2019)

Cholecystokinin induces crowing in chickens.

Scientific reports, 9(1):3978 pii:10.1038/s41598-019-40746-9.

Animals that communicate using sound are found throughout the animal kingdom. Interestingly, in contrast to human vocal learning, most animals can produce species-specific patterns of vocalization without learning them from their parents. This phenomenon is called innate vocalization. The underlying molecular basis of both vocal learning in humans and innate vocalization in animals remains unknown. The crowing of a rooster is also innately controlled, and the upstream center is thought to be localized in the nucleus intercollicularis (ICo) of the midbrain. Here, we show that the cholecystokinin B receptor (CCKBR) is a regulatory gene involved in inducing crowing in roosters. Crowing is known to be a testosterone (T)-dependent behavior, and it follows that roosters crow but not hens. Similarly, T-administration induces chicks to crow. By using RNA-sequencing to compare gene expression in the ICo between the two comparison groups that either crow or do not crow, we found that CCKBR expression was upregulated in T-containing groups. The expression of CCKBR and its ligand, cholecystokinin (CCK), a neurotransmitter, was observed in the ICo. We also showed that crowing was induced by intracerebroventricular administration of an agonist specific for CCKBR. Our findings therefore suggest that the CCK system induces innate vocalization in roosters.

RevDate: 2019-11-20

McCune KB, Jablonski P, Lee SI, et al (2019)

Captive jays exhibit reduced problem-solving performance compared to wild conspecifics.

Royal Society open science, 6(1):181311 pii:rsos181311.

Animal cognitive abilities are frequently quantified in strictly controlled settings, with laboratory-reared subjects. Results from these studies have merit for clarifying proximate mechanisms of performance and the potential upper limits of certain cognitive abilities. Researchers often assume that performance on laboratory-based assessments accurately represents the abilities of wild conspecifics, but this is infrequently tested. In this experiment, we quantified the performance of wild and captive corvid subjects on an extractive foraging task. We found that performance was not equivalent, and wild subjects were faster at problem-solving to extract the food reward. By contrast, there was no difference in the time it took for captive and wild solvers to repeat the behaviour to get additional food rewards (learning speed). Our findings differ from the few other studies that have statistically compared wild and captive performance on assessments of problem-solving and learning. This indicates that without explicitly testing it, we cannot assume that captive animal performance on experimental tasks can be generalized to the species as a whole. To better understand the causes and consequences of a variety of animal cognitive abilities, we should measure performance in the social and physical environment in which the ability in question evolved.

RevDate: 2019-03-11
CmpDate: 2019-03-11

Bauch C, Boonekamp JJ, Korsten P, et al (2019)

Epigenetic inheritance of telomere length in wild birds.

PLoS genetics, 15(2):e1007827 pii:PGENETICS-D-18-01652.

Telomere length (TL) predicts health and survival across taxa. Variation in TL between individuals is thought to be largely of genetic origin, but telomere inheritance is unusual, because zygotes already express a TL phenotype, the TL of the parental gametes. Offspring TL changes with paternal age in many species including humans, presumably through age-related TL changes in sperm, suggesting an epigenetic inheritance mechanism. However, present evidence is based on cross-sectional analyses, and age at reproduction is confounded with between-father variation in TL. Furthermore, the quantitative importance of epigenetic TL inheritance is unknown. Using longitudinal data of free-living jackdaws Corvus monedula, we show that erythrocyte TL of subsequent offspring decreases with parental age within individual fathers, but not mothers. By cross-fostering eggs, we confirmed the paternal age effect to be independent of paternal age dependent care. Epigenetic inheritance accounted for a minimum of 34% of the variance in offspring TL that was explained by paternal TL. This is a minimum estimate, because it ignores the epigenetic component in paternal TL variation and sperm TL heterogeneity within ejaculates. Our results indicate an important epigenetic component in the heritability of TL with potential consequences for offspring fitness prospects.

RevDate: 2019-11-20

Umbers KDL, White TE, De Bona S, et al (2019)

The protective value of a defensive display varies with the experience of wild predators.

Scientific reports, 9(1):463 pii:10.1038/s41598-018-36995-9.

Predation has driven the evolution of diverse adaptations for defence among prey, and one striking example is the deimatic display. While such displays can resemble, or indeed co-occur with, aposematic 'warning' signals, theory suggests deimatic displays may function independently of predator learning. The survival value of deimatic displays against wild predators has not been tested before. Here we used the mountain katydid Acripeza reticulata to test the efficacy of a putative deimatic display in the wild. Mountain katydids have a complex defence strategy; they are camouflaged at rest, but reveal a striking red-, blue-, and black-banded abdomen when attacked. We presented live katydids to sympatric (experienced) and allopatric (naive) natural predators, the Australian magpie Cracticus tibicen, and observed bird reactions and katydid behaviors and survival during repeated interactions. The efficacy of the katydids' defence differed with predator experience. Their survival was greatest when faced with naïve predators, which provided clear evidence of the protective value of the display. In contrast, katydid survival was consistently less likely when facing experienced predators. Our results suggest that sympatric predators have learned to attack and consume mountain katydids despite their complex defense, and that their post-attack display can be an effective deterrent, particularly against naïve predators. These results suggest that deimatism does not require predator learning to afford protection, but that a predator can learn to expect the display and subsequently avoid it or ignore it. That sympatric predators learn to ignore the defense is a possible explanation for the mountain katydid's counter-intuitive behavior of revealing warning colors only after tactile stimuli from predator attack.

RevDate: 2019-08-19
CmpDate: 2019-08-19

Kleider-Offutt HM (2019)

Afraid of one afraid of all: When threat associations spread across face-types.

The Journal of general psychology, 146(1):93-110.

Fear can be acquired for objects not inherently associated with threat (e.g. birds), and this threat may generalize from prototypical to peripheral category members (e.g. crows vs. penguins). When categorizing people, pervasive stereotypes link Black men to assumed violence and criminality. Faces with Afrocentric features (prototypical) are more often associated with threat and criminality than non-Afrocentric (peripheral) faces regardless of whether the individual is Black or White. In this study, using a priming paradigm, threat associations related to negative racial stereotypes were tested as a vehicle for spreading fear across face-type categories. Results showed more negative than positive judgments for White face targets but only when the prime was primarily non-Afrocentric (i.e. Eurocentric). Black face targets were judged more negatively than positively regardless of prime. This suggests some cognitive processes related to threat generalizations of objects extend to complex social categories.

RevDate: 2019-06-05
CmpDate: 2019-06-05

Rubi TL, Clark DL, Keller JS, et al (2019)

Courtship behavior and coloration influence conspicuousness of wolf spiders (Schizocosa ocreata (Hentz)) to avian predators.

Behavioural processes, 162:215-220.

Signalers must balance the benefits of detection by intended receivers with the costs of detection by eavesdroppers. This trade-off is exemplified by sexual signaling systems, in which signalers experience sexual selection for conspicuousness to mates as well as natural selection for crypsis to predators. In this study, we examined how courtship behavior and body coloration influenced the conspicuousness of males to avian predators in the well-studied brush-legged wolf spider system (Schizocosa ocreata (Hentz)). We focused on three behaviors (courtship, walking, and freezing) and two coloration schemes (natural coloration and idealized background-matching coloration). We presented captive blue jays (Cyanocitta cristata) with video playbacks of male spiders in a presence-absence detection task and characterized conspicuousness by measuring response latency and detectability. We found that any type of motion significantly increased detectability, and that body coloration and behavior interacted to determine detectability while the spiders were in motion. Among spiders in motion, courting spiders were detected faster than walking spiders. Stationary (frozen) spiders, in contrast, were rarely detected. These results illustrate that male S. ocreata can be both highly conspicuous and highly cryptic to avian predators. Thus, while we find that courtship is conspicuous to avian predators in this system, we suggest that behavioral plasticity may mitigate some of the predation costs of the sexual signal.

RevDate: 2019-11-20

Lind J (2018)

What can associative learning do for planning?.

Royal Society open science, 5(11):180778 pii:rsos180778.

There is a new associative learning paradox. The power of associative learning for producing flexible behaviour in non-human animals is downplayed or ignored by researchers in animal cognition, whereas artificial intelligence research shows that associative learning models can beat humans in chess. One phenomenon in which associative learning often is ruled out as an explanation for animal behaviour is flexible planning. However, planning studies have been criticized and questions have been raised regarding both methodological validity and interpretations of results. Due to the power of associative learning and the uncertainty of what causes planning behaviour in non-human animals, I explored what associative learning can do for planning. A previously published sequence learning model which combines Pavlovian and instrumental conditioning was used to simulate two planning studies, namely Mulcahy & Call 2006 'Apes save tools for future use.' Science312, 1038-1040 and Kabadayi & Osvath 2017 'Ravens parallel great apes in flexible planning for tool-use and bartering.' Science357, 202-204. Simulations show that behaviour matching current definitions of flexible planning can emerge through associative learning. Through conditioned reinforcement, the learning model gives rise to planning behaviour by learning that a behaviour towards a current stimulus will produce high value food at a later stage; it can make decisions about future states not within current sensory scope. The simulations tracked key patterns both between and within studies. It is concluded that one cannot rule out that these studies of flexible planning in apes and corvids can be completely accounted for by associative learning. Future empirical studies of flexible planning in non-human animals can benefit from theoretical developments within artificial intelligence and animal learning.

RevDate: 2019-11-29

Ashton BJ, Ridley AR, A Thornton (2019)

Smarter through group living: A response to Smulders.

Learning & behavior, 47(4):277-279.

We recently identified a strong, positive relationship between group size and individual cognitive performance, and a strong, positive relationship between female cognitive performance and reproductive success (Ashton, Ridley, Edwards, & Thornton in Nature, 554, 364-367, 2018). An opinion piece by Smulders (Learning & Behavior, https://doi.org/10.3758/s13420-018-0335-0, 2018) raised the interesting notion that these patterns may be underlined by motivational factors. In this commentary, we highlight why none of the available data are consistent with this explanation, but instead support the argument that the demands of group living influence cognitive development, with knock-on consequences for fitness.

RevDate: 2019-11-20

Klump BC, Masuda BM, St Clair JJH, et al (2018)

Preliminary observations of tool-processing behaviour in Hawaiian crows Corvus hawaiiensis.

Communicative & integrative biology, 11(4):e1509637.

Very few animal species habitually make and use foraging tools. We recently discovered that the Hawaiian crow is a highly skilled, natural tool user. Most captive adults in our experiment spontaneously used sticks to access out-of-reach food from a range of extraction tasks, exhibiting a surprising degree of dexterity. Moreover, many birds modified tools before or during deployment, and some even manufactured tools from raw materials. In this invited addendum article, we describe and discuss these observations in more detail. Our preliminary data, and comparisons with the better-studied New Caledonian crow, suggest that the Hawaiian crow has extensive tool-modification and manufacture abilities. To chart the full extent of the species' natural tool-making repertoire, we have started conducting dedicated experiments where subjects are given access to suitable raw materials for tool manufacture, but not ready-to-use tools.

RevDate: 2019-02-21
CmpDate: 2019-02-21

Kelly DM, Bisbing TA, JF Magnotti (2019)

Use of medial axis for reorientation by the Clark's nutcracker (Nucifraga columbiana).

Behavioural processes, 158:192-199.

Many animals are challenged with the task of reorientation. Considerable research over the years has shown a diversity of species extract geometric information (e.g., distance and direction) from continuous surfaces or boundaries to reorient. How this information is extracted from the environment is less understood. Three encoding strategies that have received the most study are the use of principal axes, medial axis or local geometric cues. We used a modeling approach to investigate which of these three general strategies best fit the spatial search data of a highly-spatial corvid, the Clark's nutcracker (Nucifraga columbiana). Individual nutcrackers were trained in a rectangular-shaped arena, and once accurately locating a hidden goal, received non-reinforced tests in an L-shaped arena. The specific shape of this arena allowed us to dissociate among the three general encoding strategies. Furthermore, we reanalyzed existing data from chicks, pigeons and humans using our modeling approach. Overall, we found the most support for the use of the medial axis, although we additionally found that pigeons and humans may have engaged in random guessing. As with our previous studies, we find no support for the use of principal axes.

RevDate: 2019-12-07
CmpDate: 2019-09-04

Cunningham CX, Johnson CN, Barmuta LA, et al (2018)

Top carnivore decline has cascading effects on scavengers and carrion persistence.

Proceedings. Biological sciences, 285(1892):.

Top carnivores have suffered widespread global declines, with well-documented effects on mesopredators and herbivores. We know less about how carnivores affect ecosystems through scavenging. Tasmania's top carnivore, the Tasmanian devil (Sarcophilus harrisii), has suffered severe disease-induced population declines, providing a natural experiment on the role of scavenging in structuring communities. Using remote cameras and experimentally placed carcasses, we show that mesopredators consume more carrion in areas where devils have declined. Carcass consumption by the two native mesopredators was best predicted by competition for carrion, whereas consumption by the invasive mesopredator, the feral cat (Felis catus), was better predicted by the landscape-level abundance of devils, suggesting a relaxed landscape of fear where devils are suppressed. Reduced discovery of carcasses by devils was balanced by the increased discovery by mesopredators. Nonetheless, carcasses persisted approximately 2.6-fold longer where devils have declined, highlighting their importance for rapid carrion removal. The major beneficiary of increased carrion availability was the forest raven (Corvus tasmanicus). Population trends of ravens increased 2.2-fold from 1998 to 2017, the period of devil decline, but this increase occurred Tasmania-wide, making the cause unclear. This case study provides a little-studied potential mechanism for mesopredator release, with broad relevance to the vast areas of the world that have suffered carnivore declines.

RevDate: 2019-08-07
CmpDate: 2019-08-07

Kent SJW, R Morrison (2018)

Rural and urban differences in orthognathic surgical patients in the north east of Scotland.

The British journal of oral & maxillofacial surgery, 56(10):931-935.

We have previously identified differences in the presentation and treatment of cancer between patients who live in rural compared with urban areas, but have not yet seen differences in those treated by orthognathic surgery. We hypothesised that patients from areas further away from the hospital face higher costs to attend and may not present with minor problems as often as those who live nearby. We therefore retrospectively reviewed all those (n=216) who had presented for orthognathic surgery over a six-year period (May 2011 to May 2017). The severity of malocclusion and facial asymmetry was established by combining measurements of intraoperative movements. Rurality was measured as the distance from home to the hospital at the time of operation. Those with smaller intraoperative movements (less than 7mm combined movement) lived significantly closer to the hospital as the crow flies (mean difference 15.13 miles, 95% CI 0.20 to 30.48, p=0.05) and could travel there more quickly (mean difference 65minutes 95% CI 9.8 to 121.7, p=0.02) than those with larger movements. Our results suggest that patients with small malocclusions and slight facial asymmetry who live further away from the hospital, may be less likely to present for operation than those who live closer. We explain why socioeconomic class is unlikely to confound our results, and suggest potential ways to minimise the effect observed.

RevDate: 2019-10-28

Amici F (2019)

An Evolutionary Approach to the Study of Collaborative Remembering?.

Topics in cognitive science, 11(4):811-816.

Hope and Gabbert (2008) and Jay and colleagues (in press) show us that collaborative remembering, in certain contexts, may result in incomplete and less accurate memories. Here, I will discuss the evolutionary origins of this behavior, linking it to phenomena such as social contagion, conformity, and social learning, which are highly adaptive and widespread across non-human taxa.

RevDate: 2019-12-02
CmpDate: 2019-12-02

Laumer IB, Call J, Bugnyar T, et al (2018)

Spontaneous innovation of hook-bending and unbending in orangutans (Pongo abelii).

Scientific reports, 8(1):16518.

Betty the crow astonished the scientific world as she spontaneously crafted hook-tools from straight wire in order to lift a basket out of vertical tubes. Recently it was suggested that this species' solution was strongly influenced by predispositions from behavioural routines from habitual hook-tool manufacture. Nevertheless, the task became a paradigm to investigate tool innovation. Considering that young humans had surprising difficulties with the task, it was yet unclear whether the innovation of a hooked tool would be feasible to primates that lacked habitual hook making. We thus tested five captive orangutans in a hook bending and unbending task. Orangutans are habitually tool-using primates that have been reported to use but not craft hooked tools for locomotion in the wild. Two orangutans spontaneously innovated hook tools and four unbent the wire from their first trial on. Pre-experience with ready-made hooks had some effect but did not lead to continuous success. Further subjects improved the hook-design feature when the task required the subjects to bent the hook at a steeper angle. Our results indicate that the ability to represent and manufacture tools according to a current need does not require stereotyped behavioural routines, but can indeed arise innovatively. Furthermore, the present study shows that the capacity for hook tool innovation is not limited to large brained birds within non-human animals.

RevDate: 2019-11-12
CmpDate: 2019-11-12

Ling H, Mclvor GE, Nagy G, et al (2018)

Simultaneous measurements of three-dimensional trajectories and wingbeat frequencies of birds in the field.

Journal of the Royal Society, Interface, 15(147):.

Tracking the movements of birds in three dimensions is integral to a wide range of problems in animal ecology, behaviour and cognition. Multi-camera stereo-imaging has been used to track the three-dimensional (3D) motion of birds in dense flocks, but precise localization of birds remains a challenge due to imaging resolution in the depth direction and optical occlusion. This paper introduces a portable stereo-imaging system with improved accuracy and a simple stereo-matching algorithm that can resolve optical occlusion. This system allows us to decouple body and wing motion, and thus measure not only velocities and accelerations but also wingbeat frequencies along the 3D trajectories of birds. We demonstrate these new methods by analysing six flocking events consisting of 50 to 360 jackdaws (Corvus monedula) and rooks (Corvus frugilegus) as well as 32 jackdaws and 6 rooks flying in isolated pairs or alone. Our method allows us to (i) measure flight speed and wingbeat frequency in different flying modes; (ii) characterize the U-shaped flight performance curve of birds in the wild, showing that wingbeat frequency reaches its minimum at moderate flight speeds; (iii) examine group effects on individual flight performance, showing that birds have a higher wingbeat frequency when flying in a group than when flying alone and when flying in dense regions than when flying in sparse regions; and (iv) provide a potential avenue for automated discrimination of bird species. We argue that the experimental method developed in this paper opens new opportunities for understanding flight kinematics and collective behaviour in natural environments.

RevDate: 2018-12-17
CmpDate: 2018-12-17

Passanha V, AD Brescovit (2018)

On the Neotropical spider Subfamily Masteriinae (Araneae, Dipluridae).

Zootaxa, 4463(1):1-73 pii:zootaxa.4463.1.1.

The Neotropical species of the diplurid subfamily Masteriinae are revised and redefined. Masteriinae now comprises four genera, Masteria L. Koch, 1893, Striamea Raven, 1981, a new genus, Siremata n. gen. and Edwa Raven, 2015, a fossil genus. The type species, Masteria hirsuta L. Koch, 1893, was used as basis for comparison and the knowledge of the genus has increased. Twelve species of Masteria are redescribed and eight new species are described: M. amarumayu n. sp. and M. mutum n. sp., from Brazil; M. yacambu n. sp., from Venezuela; M. sabrinae n. sp., from Martinique; M. tayrona n. sp., from Colombia; M. aguaruna n. sp., from Peru, M. soucouyant n. sp., from Trinidad and Tobago; and M. galipote n. sp., from the Dominican Republic. Females of Masteria aimeae (Alayón, 1995) and M. golovatchi Alayón, 1995 are described for the first time. Females of M. spinosa (Petrunkevitch, 1925), M. petrunkevitchi (Chickering, 1964), M. lewisi (Chickering, 1964), M. barona (Chickering, 1966), M. downeyi (Chickering, 1966), M. simla (Chickering, 1966), M. colombiensis Raven, 1981 and M. pecki Gertsch, 1982 are illustrated for the first time and rediagnosed. Masteria tovarensis (Simon, 1889) and M. cyclops (Simon, 1889) are synonymized with M. lucifuga (Simon, 1889). Masteria modesta (Simon, 1892) is considered as species inquirendae and M. emboaba Pedroso, Baptista Bertani, 2015 is considered as incertae sedis, as the type is lost. Both species of Striamea are revised and redescribed. A new genus, Siremata n. gen., is described and includes three Amazonian species: S. valteri n. sp., S. juruti n. sp., S. lucasae n. sp. Knowledge of the distribution ranges of the Neotropical Masteriinae are increased.

RevDate: 2018-12-21
CmpDate: 2018-12-21

Almeida MQ, Salvatierra L, JW De Morais (2018)

A new species of Masteria L. Koch, 1873 (Dipluridae: Masteriinae) from Guyana.

Zootaxa, 4434(2):366-368 pii:zootaxa.4434.2.6.

Mygalomorphs are a diverse spider group with primitive characteristics composed of the largest spider species in the world, however some species may be very small (Bond et al. 2012; Rogerio et al. 2013). The small spiders of the subfamily Masteriinae (Dipluridae, Mygalomorphae) can be found in Asia and South America (Raven 1981; Pedroso et al. 2015; WSC 2017). The subfamily is represented by two genera: Masteria L. Koch, 1873 and Striamea Raven, 1981. Masteria species can be identified by the following combination of characters: absence of cuspules in endites and labium; zero, two, six or eight eyes; and with or without paraembolic apophysis on the male palpal bulb (Raven 1981, 1985, 1991; Alayón 1995; Bertani et al. 2013; Pedroso et al. 2015). Currently, 24 species of Masteria are described, with 6 species found in South America: Masteria colombiensis, Raven, 1981 from Colombia; M. manauara Bertani, Cruz Oliveira 2013 and M. emboaba Pedroso, Baptista Bertani, 2015 from Brazil; M. cyclops (Simon 1889), M. tovarensis (Simon, 1889) and M. lucifuga (Simon, 1889) from Venezuela (WSC 2017). We document herein the first record and description of a new species of the genus Masteria from Guyana.

RevDate: 2019-03-11
CmpDate: 2019-03-11

Hausberger M, Boigné A, Lesimple C, et al (2018)

Wide-eyed glare scares raptors: From laboratory evidence to applied management.

PloS one, 13(10):e0204802.

Raptors are one of the most important causes of fatalities due to their collisions with aircrafts as well as being the main victims of collisions with constructions. They are difficult to deter because they are not influenced by other airspace users or ground predators. Because vision is the primary sensory mode of many diurnal raptors, we evaluated the reactions of captive raptors to a "superstimulus" (a "paradoxical effect whereby animals show greater responsiveness to an exaggerated stimulus than to the natural stimulus") that combined an "eye shape" stimulus (as many species have an aversion for this type of stimulus) and a looming movement (LE). This looming stimulus mimics an impending collision and induces avoidance in a wide range of species. In captivity, raptors showed a clear aversion for this LE stimulus. We then tested it in a real life setting: at an airport where raptors are abundant. This study is the first to show the efficiency of a visual non-invasive repellent system developed on the basis of both captive and field studies. This system deterred birds of prey and corvids through aversion, and did not induce habituation. These findings suggest applications for human security as well as bird conservation, and further research on avian visual perception and sensitivity to signals.

RevDate: 2019-05-06
CmpDate: 2019-05-06

Mitchell PW (2018)

The fault in his seeds: Lost notes to the case of bias in Samuel George Morton's cranial race science.

PLoS biology, 16(10):e2007008.

The discovery of nearly 180-year-old cranial measurements in the archives of 19th century American physician and naturalist Samuel George Morton can address a lingering debate, begun in the late 20th century by paleontologist and historian of science Stephen Jay Gould, about the unconscious bias alleged in Morton's comparative data of brain size in human racial groups. Analysis of Morton's lost data and the records of his studies does not support Gould's arguments about Morton's biased data collection. However, historical contextualization of Morton with his scientific peers, especially German anatomist Friedrich Tiedemann, suggests that, while Morton's data may have been unbiased, his cranial race science was not. Tiedemann and Morton independently produced similar data about human brain size in different racial groups but analyzed and interpreted their nearly equivalent results in dramatically different ways: Tiedemann using them to argue for equality and the abolition of slavery, and Morton using them to entrench racial divisions and hierarchy. These differences draw attention to the epistemic limitations of data and the pervasive role of bias within the broader historical, social, and cultural context of science.

RevDate: 2019-03-21
CmpDate: 2019-03-21

Shin DA, Kim C, Yudoyono F, et al (2018)

Feasibility of Percutaneous Robot-Assisted Epiduroscopic System.

Pain physician, 21(5):E565-E571.

BACKGROUND: Endoscopy has replaced open surgery, especially in spinal surgery. Among them, image-guided epiduroscopy allows pain generators to be identified, including epidural adhesion, fibrotic tissues, root compression, and spinal stenosis. However, the heavy lead apron worn by pain physicians to avoid exposure to radiation can induce occupational hazards, such as orthopedic complications and radiation-induced cancer. Hence, we developed a robotic system to address these problems.

OBJECTIVE: The aim of the study was to evaluate the feasibility of a robot-controlled epiduroscopic system.

STUDY DESIGN: In vivo animal experiment.

SETTING: University in Republic of Korea.

METHODS: The robot-controlled epiduroscopic system was developed using the open architecture robot system (The Raven Surgical Robotic System, CITRIS, Berkley, CA, USA). The robotic system consists of a lab-made epiduroscope, steering section, robotic arm, and manipulator. For the in vivo study, 2 Yorkshire pigs were used to simulate an epiduroscopic procedure with the robotic system.

RESULTS: The insertion and steering of the catheter was performed safely, and epiduroscopic visualization was obtained without side effects. There were no device-related complications. Radiation exposure for the primary operator was 80% lower than the levels found during conventional epiduroscopic procedures. All live pigs showed normal behavior without any signs of pain. The mean time to reach the target region was less than 8 minutes.

LIMITATIONS: The epiduroscopic procedure was performed on pigs and not on humans. The dimensions of the spinal canal of pigs cannot compare to those of humans.

CONCLUSIONS: We demonstrated the feasibility of the robot-assisted epiduroscopic system.

KEY WORDS: Epiduroscopy, robotic system, spine, pig, animal model.

RevDate: 2019-01-02
CmpDate: 2019-01-02

Elderbrock EK, Small TW, SJ Schoech (2018)

Adult Provisioning Influences Nestling Corticosterone Levels in Florida Scrub Jays (Aphelocoma coerulescens).

Physiological and biochemical zoology : PBZ, 91(6):1083-1090.

We studied Florida scrub jay (Aphelocoma coerulescens) nestlings to examine the relationship between parental feeding rates and levels of corticosterone (CORT), a metabolic and stress-related steroid hormone hypothesized to play a role in mediating begging behavior. It has been documented that nutritional deficiency results in increased glucocorticoid levels in nestling birds. Further, previous studies have found that CORT levels of Florida scrub jay nestlings are negatively correlated with parental nest attendance and provisioning rates; however, the behavioral observations were made several days before the collection of samples to assess CORT levels. Few studies have investigated whether experience immediately before sampling impacts nestling glucocorticoid levels, especially in a free-living species. By monitoring parental activity at the nest before sample collection, we found that nestling CORT levels varied as a function of parental provisioning rate and the time since their last feed. However, counter to our predictions, higher provisioning rates and more recent feedings were associated with higher CORT levels in nestlings rather than lower CORT levels. These results suggest that some aspect of parental provisioning results in increased CORT levels in nestling Florida scrub jays.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Ganz K, Jenni L, Madry MM, et al (2018)

Acute and Chronic Lead Exposure in Four Avian Scavenger Species in Switzerland.

Archives of environmental contamination and toxicology, 75(4):566-575.

Despite irrefutable evidence of its negative impact on animal behaviour and physiology, lethal and sublethal lead poisoning of wildlife is still persistent and widespread. For scavenging birds, ingestion of ammunition, or fragments thereof, is the major exposure route. In this study, we examined the occurrence of lead in four avian scavengers of Switzerland and how it differs between species, regions, and age of the bird. We measured lead concentration in liver and bone of the two main alpine avian scavengers (golden eagle Aquila chrysaetos and bearded vulture Gypaetus barbatus) over the entire area of the Swiss Alps and two of the main avian scavengers occurring in the lowlands of Switzerland (red kite Milvus milvus and common raven Corvus corax). Of those four species, only the bearded vulture is an obligate scavenger. We found that lead burdens in the two alpine avian scavengers were higher than those found for the same species elsewhere in Europe or North America and reached levels compatible with acute poisoning, whereas lead burdens of the two lowland avian scavengers seemed to be lower. Several golden eagles, but only one red kite with abnormally high bone lead concentrations were found. In all four species, a substantial proportion of birds had elevated levels which presumably represent recent (liver lead levels) or past (bone lead levels) uptake of sublethal doses of lead.

RevDate: 2019-11-29
CmpDate: 2019-11-29

Townsend AK, Taff CC, Jones ML, et al (2019)

Apparent inbreeding preference despite inbreeding depression in the American crow.

Molecular ecology, 28(5):1116-1126.

Although matings between relatives can have negative effects on offspring fitness, apparent inbreeding preference has been reported in a growing number of systems, including those with documented inbreeding depression. Here, we examined evidence for inbreeding depression and inbreeding preference in two populations (Clinton, New York, and Davis, California, USA) of the cooperatively breeding American crow (Corvus brachyrhynchos). We then compared observed inbreeding strategies with theoretical expectations for optimal, adaptive levels of inbreeding, given the inclusive fitness benefits and population-specific magnitude of inbreeding depression. We found that low heterozygosity at a panel of 33 microsatellite markers was associated with low survival probability (fledging success) and low white blood cell counts among offspring in both populations. Despite these costs, our data were more consistent with inbreeding preference than avoidance: The observed heterozygosity among 396 sampled crow offspring was significantly lower than expected if local adults were mating by random chance. This pattern was consistent across a range of spatial scales in both populations. Adaptive levels of inbreeding, given the magnitude of inbreeding depression, were predicted to be very low in the California population, whereas complete disassortative mating was predicted in the New York population. Sexual conflict might have contributed to the apparent absence of inbreeding avoidance in crows. These data add to an increasing number of examples of an "inbreeding paradox," where inbreeding appears to be preferred despite inbreeding depression.

RevDate: 2019-11-14
CmpDate: 2019-11-14

Taufique SKT, Prabhat A, V Kumar (2018)

Illuminated night alters hippocampal gene expressions and induces depressive-like responses in diurnal corvids.

The European journal of neuroscience, 48(9):3005-3018.

Artificial light at night induces circadian disruptions and causes cognitive impairment and mood disorders; yet very little is known about the neural and molecular correlates of these effects in diurnal animals. We manipulated the night environment and examined cellular and molecular changes in hippocampus, the brain region involved in cognition and mood, of Indian house crows (Corvus splendens) exposed to 12 hr light (150 lux): 12 hr darkness (0 lux). Diurnal corvids are an ideal model species with cognitive abilities at par with mammals. Dim light (6 lux) at night (dLAN) altered daily activity:rest pattern, reduced sleep, and induced depressive-like responses (decreased eating and self-grooming, self-mutilation, and reduced novel object exploration); return to an absolute dark night reversed these negative effects. dLAN suppressed nocturnal melatonin levels; however, diurnal corticosterone levels were unaffected. Concomitant reduction of immunoreactivity for DCX and BDNF suggested dLAN-induced suppression of hippocampal neurogenesis and compromised neuronal health. dLAN also negatively influenced hippocampal expression of genes associated with depressive-like responses (bdnf, il-1β, tnfr1, nr4a2), but not of those associated with neuronal plasticity (egr1, creb, syngap, syn2, grin2a, grin2b), cellular oxidative stress (gst, sod3, cat1) and neuronal death (caspase2, caspase3, foxo3). Furthermore, we envisaged the role of BDNF and showed epigenetic modification of bdnf gene by decreased histone H3 acetylation and increased hdac4 expression under dLAN. These results demonstrate transcriptional and epigenetic bases of dLAN-induced negative effects in diurnal crows, and provide insights into the risks of exposure to illuminated nights to animals including humans in an urban setting.

RevDate: 2019-11-20

Simonds VW, Kim FL, LaVeaux D, et al (2019)

Guardians of the Living Water: Using a Health Literacy Framework to Evaluate a Child as Change Agent Intervention.

Health education & behavior : the official publication of the Society for Public Health Education, 46(2):349-359.

BACKGROUND: American Indian communities in the United States experience considerable health inequities, including increased exposure to environmental contaminants. Consequently, community members of the Apsáalooke (Crow) Nation identified the lack of water-related environmental knowledge among children as an area of concern.

AIM: The purpose of this study was to provide a feasibility evaluation of an increasingly sophisticated environmental health literacy program for children.

METHOD: A community-academic partnership developed and piloted the Guardians of the Living Water program to increase environmental health literacy among children and their families on the Crow reservation. Nutbeam's framework for health literacy, a schema based on functional, interactive, and critical literacy, shaped the program evaluation. We used a within-subjects, quasi-experimental design without a control group. Interviews with children and parents were used to assess the feasibility of the program, while pre-/posttests assessed changes in knowledge, skills, and behavior.

RESULTS: Compared with preintervention responses, those from postintervention indicated significant increases for selected knowledge and attitude components. Based on qualitative interviews with children and caregivers, the camp was a valuable experience and increased knowledge of water quality science and reinforced cultural knowledge.

DISCUSSION: This success of our program stems from the trust initially built between partners and then expanded throughout the community. The program and the evaluation benefited from both the health literacy framework and from our integration of Apsáalooke values.

CONCLUSION: Our findings suggest that a community-based intervention designed to increase environmental health literacy among youth and their social networks is feasible and acceptable to this American Indian community.

RevDate: 2019-10-02
CmpDate: 2019-10-02

Wheatcroft D, TD Price (2018)

Collective Action Promoted by Key Individuals.

The American naturalist, 192(4):401-414.

Explaining why individuals participate in risky group behaviors has been a long-term challenge. We experimentally studied the formation of groups of birds (mobs) that aggressively confront predators and avian nest parasites and developed a theoretical model to evaluate the conditions under which mobs arise. We presented taxidermied mounts of predators on adult birds (hawks and owls) and of nest threats (crows and cuckoos) at different distances to nests of Phylloscopus warblers. Even when alone, birds are aggressive toward predators of adult birds, both at and away from their nests. By contrast, birds aggressively confront nest threats alone only when they have a nest nearby. However, strong initial responses by nest owners lead individuals without nearby nests to increase their responses, thereby generating a mob. Building on these findings, we derive the conditions in which individuals are incentivized to invest more when joining a high-gain individual compared to when acting alone. Strong responses of high-gain individuals acting alone tend to reduce the investments of other high-gain individuals that subsequently join. However, individuals that benefit sufficiently little from acting alone increase their investments when joining a high-gain individual and can even be sufficiently incentivized to join in when they would otherwise not act alone. Together, these results suggest an important role for key individuals in the generation of some group behaviors.

RevDate: 2018-11-14
CmpDate: 2018-11-01

Hennefield L, Hwang HG, Weston SJ, et al (2018)

Meta-analytic techniques reveal that corvid causal reasoning in the Aesop's Fable paradigm is driven by trial-and-error learning.

Animal cognition, 21(6):735-748.

The classic Aesop's fable, Crow and the Pitcher, has inspired a major line of research in comparative cognition. Over the past several years, five articles (over 32 experiments) have examined the ability of corvids (e.g., rooks, crows, and jays) to complete lab-based analogs of this fable, by requiring them to drop stones and other objects into tubes of water to retrieve a floating worm (Bird and Emery in Curr Biol 19:1-5, 2009b; Cheke et al. in Anim Cogn 14:441-455, 2011; Jelbert et al. in PLoS One 3:e92895, 2014; Logan et al. in PLoS One 7:e103049, 2014; Taylor et al. in Gray R D 12:e26887, 2011). These researchers have stressed the unique potential of this paradigm for understanding causal reasoning in corvids. Ghirlanda and Lind (Anim Behav 123:239-247, 2017) re-evaluated trial-level data from these studies and concluded that initial preferences for functional objects, combined with trial-and-error learning, may account for subjects' performance on key variants of the paradigm. In the present paper, we use meta-analytic techniques to provide more precise information about the rate and mode of learning that occurs within and across tasks. Within tasks, subjects learned from successful (but not unsuccessful) actions, indicating that higher-order reasoning about phenomena such as mass, volume, and displacement is unlikely to be involved. Furthermore, subjects did not transfer information learned in one task to subsequent tasks, suggesting that corvids do not engage with these tasks as variants of the same problem (i.e., how to generate water displacement to retrieve a floating worm). Our methodological analysis and empirical findings raise the question: Can Aesop's fable studies distinguish between trial-and-error learning and/or higher-order causal reasoning? We conclude they cannot.

RevDate: 2019-10-24
CmpDate: 2019-10-24

Mason LD, Wardell-Johnson G, Luxton SJ, et al (2018)

Predators Show Seasonal Predilections for Model Clay Spiders in an Urban Environment.

Scientific reports, 8(1):12444.

Predator-prey interactions may be altered under human-induced rapid environmental change, such as urbanisation. Extensive clearing in urban areas may leave short-range endemic species, such as mygalomorph spiders, more vulnerable to local extinction through predation in remaining remnants. Predation rates on Australian mygalomorph spiders were assessed using clay models of two size classes (5 cm, 3 cm), during two time periods in 2016 (January-February, July-August). Size and phenology of models resembled the mygalomorph genera Aname and Teyl occurring in these local urban remnants. Local predator guilds were significantly influenced by leaf-litter cover (%) and proportion of surrounding parkland. Preference for spider vs. control models was consistent across all predator types (bird, rodent, lizard and wasp), but specialist spider wasps (Pompilidae) only attacked spider models. Generalist predators (birds, lizards and rodents) were more opportunistic. Lizards and rodents exhibit similar predation behaviour, indicating there may be some inter-specific competition. Invasive generalists (e. g. rodents) or urban adapters (e. g. corvids) are more likely to represent an increased threat to spiders than are co-evolved specialists (e.g. spider wasps).

RevDate: 2019-08-26
CmpDate: 2019-08-26

Steyaert SMJG, Frank SC, Puliti S, et al (2018)

Special delivery: scavengers direct seed dispersal towards ungulate carcasses.

Biology letters, 14(8):.

Cadaver decomposition islands around animal carcasses can facilitate establishment of various plant life. Facultative scavengers have great potential for endozoochory, and often aggregate around carcasses. Hence, they may disperse plant seeds that they ingest across the landscape towards cadaver decomposition islands. Here, we demonstrate this novel mechanism along a gradient of wild tundra reindeer carcasses. First, we show that the spatial distribution of scavenger faeces (birds and foxes) was concentrated around carcasses. Second, faeces of the predominant scavengers (corvids) commonly contained viable seeds of crowberry, a keystone species of the alpine tundra with predominantly vegetative reproduction. We suggest that cadaver decomposition islands function as endpoints for directed endozoochory by scavengers. Such a mechanism could be especially beneficial for species that rely on small-scale disturbances in soil and vegetation, such as several Nordic berry-producing species with cryptic generative reproduction.

RevDate: 2019-08-22
CmpDate: 2019-08-22

Campo JV, JA Bridge (2018)

Exploring the Impact of 13 Reasons Why: Looking for Light Amidst the Heat . . .

Journal of the American Academy of Child and Adolescent Psychiatry, 57(8):547-549.

A Letter to the Editor by Kieling and collegues1 in this month's Journal attempts to explore the impact of the Netflix series 13 Reasons Why (13RW) on the thinking and behavior of adolescent viewers. The series is an adaptation of a 2007 novel by Jay Asher, and tells the story of an adolescent girl who dies by suicide following a series of traumas and disappointments that she catalogues before her death on 13 audiotapes. The tapes are left behind with the expectation that each of the individuals presumably responsible for her suicide will listen and better understand their individual and collective failures. Since its release and airing in 2017, the show has generated considerable heated debate and controversy, largely due to concerns about its potential for suicide contagion.

RevDate: 2019-11-20

Sutton JT, Helmkampf M, Steiner CC, et al (2018)

A High-Quality, Long-Read De Novo Genome Assembly to Aid Conservation of Hawaii's Last Remaining Crow Species.

Genes, 9(8):.

Abstract: Genome-level data can provide researchers with unprecedented precision to examine the causes and genetic consequences of population declines, which can inform conservation management. Here, we present a high-quality, long-read, de novo genome assembly for one of the world's most endangered bird species, the 'Alalā (Corvus hawaiiensis; Hawaiian crow). As the only remaining native crow species in Hawai'i, the 'Alalā survived solely in a captive-breeding program from 2002 until 2016, at which point a long-term reintroduction program was initiated. The high-quality genome assembly was generated to lay the foundation for both comparative genomics studies and the development of population-level genomic tools that will aid conservation and recovery efforts. We illustrate how the quality of this assembly places it amongst the very best avian genomes assembled to date, comparable to intensively studied model systems. We describe the genome architecture in terms of repetitive elements and runs of homozygosity, and we show that compared with more outbred species, the 'Alalā genome is substantially more homozygous. We also provide annotations for a subset of immunity genes that are likely to be important in conservation management, and we discuss how this genome is currently being used as a roadmap for downstream conservation applications.

RevDate: 2019-09-05
CmpDate: 2019-07-30

Gonçalves A, D Biro (2018)

Comparative thanatology, an integrative approach: exploring sensory/cognitive aspects of death recognition in vertebrates and invertebrates.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 373(1754):.

Evolutionary thanatology benefits from broad taxonomic comparisons of non-human animals' responses to death. Furthermore, exploring the sensory and cognitive bases of these responses promises to allow classification of the underlying mechanisms on a spectrum from phylogenetically ancient to more derived traits. We draw on studies of perception and cognition in invertebrate and vertebrate taxa (with a focus on arthropods, corvids, proboscids, cetaceans and primates) to explore the cues that these animals use to detect life and death in others, and discuss proximate and ultimate drivers behind their capacities to do so. Parallels in thanatological behaviour exhibited by the last four taxa suggest similar sensory-cognitive processing rules for dealing with corpses, the evolution of which may have been driven by complex social environments. Uniting these responses is a phenomenon we term 'animacy detection malfunction', whereupon the corpse, having both animate and inanimate attributes, creates states of fear/curiosity manifested as approach/avoidance behaviours in observers. We suggest that integrating diverse lines of evidence (including the 'uncanny valley' effect originating from the field of robotics) provides a promising way to advance the field, and conclude by proposing avenues for future research.This article is part of the theme issue 'Evolutionary thanatology: impacts of the dead on the living in humans and other animals'.

RevDate: 2019-09-05
CmpDate: 2019-07-30

Swift K, JM Marzluff (2018)

Occurrence and variability of tactile interactions between wild American crows and dead conspecifics.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 373(1754):.

Observations of some mammals and birds touching their dead provoke questions about the motivation and adaptive value of this potentially risky behaviour. Here, we use controlled experiments to determine if tactile interactions are characteristic of wild American crow responses to dead crows, and what the prevalence and nature of tactile interactions suggests about their motivations. In Experiment 1, we test if food or information acquisition motivates contact by presenting crows with taxidermy-prepared dead crows, and two species crows are known to scavenge: dead pigeons and dead squirrels. In Experiment 2, we test if territoriality motivates tactile interactions by presenting crows with taxidermy crows prepared to look either dead or upright and life-like. In Experiment 1, we find that crows are significantly less likely to make contact but more likely to alarm call and recruit other birds in response to dead crows than to dead pigeons and squirrels. In addition, we find that aggressive and sexual encounters with dead crows are seasonally biased. These findings are inconsistent with feeding or information acquisition-based motivation. In Experiment 2, we find that crows rarely dive-bomb and more often alarm call and recruit other crows to dead than to life-like crows, behaviours inconsistent with responses given to live intruders. Consistent with a danger response hypothesis, our results show that alarm calling and neighbour recruitment occur more frequently in response to dead crows than other stimuli, and that touching dead crows is atypical. Occasional contacts, which take a variety of aggressive and sexual forms, may result from an inability to mediate conflicting stimuli.This article is part of the theme issue 'Evolutionary thanatology: impacts of the dead on the living in humans and other animals'.

RevDate: 2019-11-25
CmpDate: 2019-11-25

Gómez-Olivencia A, Sala N, Núñez-Lahuerta C, et al (2018)

First data of Neandertal bird and carnivore exploitation in the Cantabrian Region (Axlor; Barandiaran excavations; Dima, Biscay, Northern Iberian Peninsula).

Scientific reports, 8(1):10551.

Neandertals were top predators who basically relied on middle- to large-sized ungulates for dietary purposes, but there is growing evidence that supports their consumption of plants, leporids, tortoises, marine resources, carnivores and birds. The Iberian Peninsula has provided the most abundant record of bird exploitation for meat in Europe, starting in the Middle Pleistocene. However, the bird and carnivore exploitation record was hitherto limited to the Mediterranean area of the Iberian Peninsula. Here we present the first evidence of bird and carnivore exploitation by Neandertals in the Cantabrian region. We have found cut-marks in two golden eagles, one raven, one wolf and one lynx remain from the Mousterian levels of Axlor. The obtaining of meat was likely the primary purpose of the cut-marks on the golden eagle and lynx remains. Corvids, raptors, felids and canids in Axlor could have likely acted as commensals of the Neandertals, scavenging upon the carcasses left behind by these hunter-gatherers. This could have brought them closer to Neandertal groups who could have preyed upon them. These new results provide additional information on their dietary scope and indicate a more complex interaction between Neandertals and their environment.

RevDate: 2019-11-26

Smulders TV (2019)

Smarter through group living?.

Learning & behavior, 47(4):275-276.

Wild Australian magpies living (or growing up) in larger social groups take fewer trials to solve a battery of four cognitive tests than those living (or growing up) in smaller groups. The tests all draw on a common underlying factor, but is this factor cognitive or motivational?


RJR Experience and Expertise


Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.


Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.


Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.


Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.


While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.


Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.


Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.


Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.

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This is a must read book for anyone with an interest in invasion biology. The full title of the book lays out the author's premise — The New Wild: Why Invasive Species Will Be Nature's Salvation. Not only is species movement not bad for ecosystems, it is the way that ecosystems respond to perturbation — it is the way ecosystems heal. Even if you are one of those who is absolutely convinced that invasive species are actually "a blight, pollution, an epidemic, or a cancer on nature", you should read this book to clarify your own thinking. True scientific understanding never comes from just interacting with those with whom you already agree. R. Robbins

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Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

Research Gate page for R J Robbins

ResearchGate is a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a study by Nature and an article in Times Higher Education , it is the largest academic social network in terms of active users.

Curriculum Vitae for R J Robbins

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Curriculum Vitae for R J Robbins

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RJR Picks from Around the Web (updated 11 MAY 2018 )