Behavioral flexibility in an invasive bird is independent of other behaviors.

Behavioral flexibility is considered important for a species to adapt to environmental change. However, it is unclear how behavioral flexibility works: it relates to problem solving ability and speed in unpredictable ways, which leaves an open question of whether behavioral flexibility varies with differences in other behaviors. If present, such correlations would mask which behavior causes individuals to vary. I investigated whether behavioral flexibility (reversal learning) performances were linked with other behaviors in great-tailed grackles, an invasive bird. I found that behavioral flexibility did not significantly correlate with neophobia, exploration, risk aversion, persistence, or motor diversity. This suggests that great-tailed grackle performance in behavioral flexibility tasks reflects a distinct source of individual variation. Maintaining multiple distinct sources of individual variation, and particularly variation in behavioral flexibility, may be a mechanism for coping with the diversity of novel elements in their environments and facilitate this species' invasion success.This is the published version. It first appeared at https://peerj.com/articles/2215/reviews/

Behavioral flexibility and problem solving in an invasive bird.

Behavioral flexibility is considered an important trait for adapting to environmental change, but it is unclear what it is, how it works, and whether it is a problem solving ability. I investigated behavioral flexibility and problem solving experimentally in great-tailed grackles, an invasive bird species and thus a likely candidate for possessing behavioral flexibility. Grackles demonstrated behavioral flexibility in two contexts, the Aesop's Fable paradigm and a color association test. Contrary to predictions, behavioral flexibility did not correlate across contexts. Four out of 6 grackles exhibited efficient problem solving abilities, but problem solving efficiency did not appear to be directly linked with behavioral flexibility. Problem solving speed also did not significantly correlate with reversal learning scores, indicating that faster learners were not the most flexible. These results reveal how little we know about behavioral flexibility, and provide an immense opportunity for future research to explore how individuals and species can use behavior to react to changing environments.This is the final version. It first appeared from PeerJ at https://doi.org/10.7717/peerj.1975

Bothrops asper (Terciopelo) scavenging behavior

This is the final version of the article. It first appeared from Society for the Study of Amphibians and Reptiles via https://www.zenscientist.com/index.php/pdflibrary2/func-finishdown/129/This research was sponsored by the Gates Cambridge Trust

Social learning is central to innovation, in primates and beyond

AbstractMuch of the importance of innovation stems from its capacity to spread via social learning, affecting multiple individuals, thus generating evolutionary and ecological consequences. We advocate a broader taxonomic focus in the field of behavioral innovation, as well as the use of comparative field research, and discuss the unique conservation implications of animal innovations and traditions.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/S0140525X0700247

Validating methods for estimating endocranial volume in individual red deer (Cervus elaphus).

Comparing brain sizes is a key method in comparative cognition and evolution. Brain sizes are commonly validated by interspecific comparisons involving animals of varying size, which does not provide a realistic index of their accuracy for intraspecific comparisons. Intraspecific validation of methods for measuring brain size should include animals of the same age and sex to ensure that individual differences can be detected in animals of similar size. In this study we compare three methods of measuring the endocranial volume of 33 red deer skulls to investigate the accuracy of each method. Methods for estimating endocranial volume included scanning each skull using computerised tomography (CT) and quantifying the volume with OsiriX software, filling the cranium with glass beads and measuring the bead volume, and linear measurements (length, width, and height) of the cranium using callipers. CT scan volumes were highly correlated with results from the bead method, but only moderately correlated with the linear method. This study illustrates the importance of validating intraspecies measurement methods, which allows for the accurate interpretation of results.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.beproc.2012.10.01

Specializations of birds that attend army ant raids: an ecological approach to cognitive and behavioral studies.

Tropical birds forage at army ant raids on several continents. Obligate foraging at army ant raids evolved several times in the Neotropical true antbird family (Thamnophilidae), and recent evidence suggests a diversity of bird species from other families specialize to varying degrees on army ant exploitation. Army ant raids offer access to high prey densities, but the ant colonies are mobile and widely spaced. Successful army ant exploitation requires solving a complex foraging problem because army ant raids are unpredictable in space and time. Birds can counteract the challenges posed by the ants by using strategies that raise their chances of detecting army ant raids, and birds can use additional strategies to track army ant colonies they have located. Some features of army ant biology, such as their conspicuous swarms and columns, above-ground activity, and regular cycles of behavior, provide opportunities for birds to increase their effectiveness at exploiting raids. Changes in sensory, cognitive and behavioral systems may all contribute to specialized army ant exploitation in a bird population. The combination of specializations that are employed may vary independently among bird species and populations. The degree of army ant exploitation by birds varies geographically with latitude and elevation, and with historical patterns such as centers of distribution of obligate thamnophilid antbirds. We predict the set of specializations a given bird population exhibits will depend on local ecology, as well as phylogenetic history. Comparative approaches that focus on these patterns may indicate ecological and evolutionary factors that have shaped the costs and benefits of this foraging strategy. The development of army ant exploitation in individual birds is poorly understood, and individual expression of these specializations may depend on a combination of genetic adaptation with cognitive plasticity, possibly including social and experiential learning. Future studies that measure developmental changes and quantify individual differences in army ant exploitation are needed to establish the mechanisms underlying this behavior.This work was supported by National Science Foundation grant IOS-1209072 and Drexel University funds (to S.O’D.); the Gates Cambridge Scholarship and Murray Edwards College Overseas Bursary (to C.L.); and the University of Cambridge, Clare College and BBSRC (to N.S.C.).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.beproc.2012.09.00

Modifications to the Aesop's Fable paradigm change New Caledonian crow performances

While humans are able to understand much about causality, it is unclear to what extent non-human animals can do the same. The Aesop's Fable paradigm requires an animal to drop stones into a water-filled tube to bring a floating food reward within reach. Rook, Eurasian jay, and New Caledonian crow performances are similar to those of children under seven years of age when solving this task. However, we know very little about the cognition underpinning these birds' performances. Here, we address several limitations of previous Aesop's Fable studies to gain insight into the causal cognition of New Caledonian crows. Our results provide the first evidence that any non-human animal can solve the U-tube task and can discriminate between water-filled tubes of different volumes. However, our results do not provide support for the hypothesis that these crows can infer the presence of a hidden causal mechanism. They also call into question previous object-discrimination performances. The methodologies outlined here should allow for more powerful comparisons between humans and other animal species and thus help us to determine which aspects of causal cognition are distinct to humans.Publisher PDFPeer reviewe

Western scrub-jays do not appear to attend to functionality in Aesop's Fable experiments.

Western scrub-jays are known for their highly discriminatory and flexible behaviors in a caching (food storing) context. However, it is unknown whether their cognitive abilities are restricted to a caching context. To explore this question, we tested scrub-jays in a non-caching context using the Aesop's Fable paradigm, where a partially filled tube of water contains a floating food reward and objects must be inserted to displace the water and bring the food within reach. We tested four birds, but only two learned to drop stones proficiently. Of these, one bird participated in 4/5 experiments and one in 2/5 experiments. Both birds passed one experiment, but without attending to the functional differences of the objects, and failed the other experiments. Scrub-jays were not motivated to participate in these experiments, suggesting that either this paradigm was ecologically irrelevant or perhaps their flexibility is restricted to a caching context.This is the final version of the article. It first appeared from PeerJ via http://dx.doi.org/10.7717/peerj.170

How New Caledonian crows solve novel foraging problems and what it means for cumulative culture.

New Caledonian crows make and use tools, and tool types vary over geographic landscapes. Social learning may explain the variation in tool design, but it is unknown to what degree social learning accounts for the maintenance of these designs. Indeed, little is known about the mechanisms these crows use to obtain information from others, despite the question's importance in understanding whether tool behavior is transmitted via social, genetic, or environmental means. For social transmission to account for tool-type variation, copying must utilize a mechanism that is action specific (e.g., pushing left vs. right) as well as context specific (e.g., pushing a particular object vs. any object). To determine whether crows can copy a demonstrator's actions as well as the contexts in which they occur, we conducted a diffusion experiment using a novel foraging task. We used a nontool task to eliminate any confounds introduced by individual differences in their prior tool experience. Two groups had demonstrators (trained in isolation on different options of a four-option task, including a two-action option) and one group did not. We found that crows socially learn about context: After observers see a demonstrator interact with the task, they are more likely to interact with the same parts of the task. In contrast, observers did not copy the demonstrator's specific actions. Our results suggest it is unlikely that observing tool-making behavior transmits tool types. We suggest it is possible that tool types are transmitted when crows copy the physical form of the tools they encounter.We are grateful to our funders: the SAGE Center for the Study of the Mind at the University of California Santa Barbara and the National Geographic Society/Waitt Grants Program (CJL), a Rutherford Discovery Fellowship from the Royal Society of New Zealand (AHT), the Marsden Fund (RG), and a BBSRC grant (WH; BB/I007997/1).This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.3758/s13420-015-0194-

Western scrub-jays do not appear to attend to functionality in Aesop’s Fable experiments

Western scrub-jays are known for their highly discriminatory and flexible behaviors in a caching (food storing) context. However, it is unknown whether their cognitive abilities are restricted to a caching context. To explore this question, we tested scrub-jays in a noncaching context using the Aesop's Fable paradigm, where a partially filled tube of water contains a floating food reward and objects must be inserted to displace the water and bring the food within reach. We found that scrub-jays did not attend to the functional properties of objects or tubes, and were not motivated to participate in these experiments, suggesting that either this paradigm was ecologically irrelevant or perhaps their flexibility is restricted to a caching context. PeerJ PrePrints | https://doi.org/10.7287/peerj.preprints.1616v1 | CC-BY 4.0 Open Access