Greggor, A. L. | Search bioRxiv

bioRxiv2021

Individual repeatability, species differences, and the influence of socio-ecological factors on neophobia in 10 corvid species

Behavioural responses to novelty, including fear and subsequent avoidance of novel stimuli, behaviours referred to as neophobia, determine how animals interact with their environment. Neophobia aids in navigating risk and impacts on adaptability and survival. There is variation within and between individuals and species, however, lack of large-scale, comparative studies critically limits investigation of the socio-ecological drivers of neophobia. In this study, we tested responses to novel objects and food (alongside familiar food) versus a baseline (familiar food alone) in 10 corvid species (241 subjects) across 10 labs worldwide. There were species differences in the latency to touch familiar food in the novel object and food conditions relative to the baseline. Three of seven socio-ecological factors influenced object neophobia: 1) use of urban habitat (vs not), 2) territorial pair vs family group sociality and 3) large vs small flock size (whereas range, caching, hunting live animals, and genus did not); while only flock size influenced food neophobia. We found that, overall, individuals were temporally and contextually repeatable (i.e. consistent) in their novelty responses in all conditions, indicating neophobia is a stable behavioural trait. With this study, we have established a network of corvid researchers, demonstrating potential for further collaboration to explore the evolution of cognition in corvids and other bird species. These novel findings enable us, for the first time in corvids, to identify the socio-ecological correlates of neophobia and grant insight into specific elements that drive higher neophobic responses in this avian family group.

animal behavior and cognition↗

bioRxiv2021

Testing the maintenance of natural responses to survival-relevant calls in the conservation breeding population of a critically endangered corvid (Corvus hawaiiensis)

Vocal communication serves an important role in driving many animals social interactions and ultimately their survival. However, both the structure of and responses towards natural vocal behavior can be lost or subject to alteration under human care. Determining if animals in conservation breeding programs exhibit and respond appropriately to species-specific vocalizations is therefore important for ensuring their survival and persistence post-release. We tested whether endangered alal[a] (Corvus hawaiiensis), which are extinct in nature, have retained their natural responses to vocal calls that were previously linked to survival and reproduction in the wild. We conducted our studies on breeding populations derived from a small number of founding alal[a] maintained under human care since their extinction in the wild in 2002. We presented pairs of alal[a] with alarm, territorial intrusion, and two types of control playback calls (a non-threatening territorial maintenance call and a novel heterospecific call). Alal[a] were significantly more likely to approach the speaker following alarm call playback than other call types, and were more likely to respond to territorial intrusion calls with the same aggressive territorial calls. Males were more likely to make these aggressive calls than females, mirroring their roles in territory defense. We also found individual consistency in the level of vocal behavior response across all call types, indicating that some individuals are more vocal than others. These results are encouraging, showing that alal[a] exhibit relevant, species-specific behaviors despite generations under human care. They do illustrate, however, that not all individuals respond appropriately, so animals responses to vocal stimuli may be an important factor to consider in determining the release suitability of individuals. Significance StatementEffective communication is crucial to the survival of many animals, but can erode without natural selection. Therefore, testing the flexibility and maintenance of communication and vocal responses in contexts where animals are isolated from conspecifics or from survival consequences, such as in conservation breeding centers, can help determine species susceptibility to communication loss. We used playbacks of survival-related conspecific calls to test if alal[a] (Corvus hawaiiensis), retained species-specific responses to these calls after generations under human care. We found that birds maintained a species-level natural response, however these natural responses were not consistent across individuals, suggesting that some birds may not be well equipped to survive in the wild without additional training or care.

animal behavior and cognition↗