Animal Cognition最新文献

Understanding vocal communication is essential to unraveling avian social behavior and cognition; however, audio recording remains particularly challenging in field studies involving wild populations. In this study, we deployed a lightweight, multi-sensor biologging device (MiniDTAG) designed for medium- to large-sized birds. The device integrates a microphone, accelerometer, magnetometer, and pressure sensors into a 12.5 g package, enabling high-fidelity acoustic and behavioral data collection. We deployed 52 MiniDTAGs over three breeding seasons in free-ranging cooperatively breeding carrion crows (Corvus corone) in northern Spain. The auto-releasing attachment method allowed the birds to free themselves from the tag after 18.5 days, on average. We recovered 87% tags, collecting over 83 h of data per device on average. Using a machine learning model (Voxaboxen), we detected over 127,000 vocalizations and assigned them to focal tagged individuals, adult conspecifics, crow chicks, and parasitic great spotted cuckoo nestlings (Clamator glandarius) with high precision and recall. We also explored the potential of accelerometer data to identify specific behaviors within a cooperative context, namely anti-predator mobbing. To evaluate logger impact, we analyzed 825 h of video from 22 crow groups and found minimal effects on brood feeding rates and reproductive success. Our results highlight the MiniDTAG’s potential to advance the study of animal communication by capturing vocalizations across the whole range of amplitudes. This approach opens new avenues for exploring the mechanisms of cooperation and information exchange in complex social systems and lays the groundwork for future comparative studies in corvid communication.

Bioacoustic parameters of vocalization are generally well adapted to the environment that the species inhabits and are influenced by the morphology and life history of the species. These effects are frequently studied on bird songs; however, little is known about how ecology, phylogeny and morphology affect alarm calls. We investigated these factors in the crow family (Corvidae, Passeriformes) that exhibits extensive distribution around the world and is well known for their variable, conspicuous alarm calls. Using a free database of sounds (xeno-canto) as well as own recordings, we collected alarm calls of 66 species representing 21 out of 24 genera within the family. We measured four vocal characteristics, which showed high variability among the family and low mutual correlation – peak frequency, peak frequency change, harmonicity and call duration. The effect of body mass and preferred habitat openness of the species on these four parameters was tested using phylogenetic regression. We also assessed the strength of the phylogenetic signal. Peak frequency, peak frequency change and harmonicity were influenced by phylogeny, while the alarm call duration evolved independently of phylogeny. Body mass significantly affects the mean peak frequency with bigger species producing sounds of lower frequency. Additionally, the openness of the preferred habitat of the species significantly affects the maximum change in peak frequency. Forest species show less peak frequency fluctuation within the alarm call, probably because dense vegetation does not favour good transmission of highly modulated signals. We conclude, that features of corvid alarm calls are affected by similar drivers as e.g. bird song.

Avoiding predation is essential for most animals. For group-living species, effective predator avoidance relies on making fast and accurate collective decisions. However, the mechanisms underlying the ability to make adaptive collective decisions and to coordinate movements under predation threat remains unclear. Here, we used guppies artificially selected for divergence in the size of the telencephalon, the main brain region for advanced decision-making in vertebrates, to test the influence of telencephalon size on collective decision-making under predation threat. We measured the latency and accuracy of collective decision-making to avoid a model predator in guppy shoals. In addition, we used high-resolution tracking analysis to assess shoaling dynamics under predator threat between the telencephalon size selection lines. We found that collective decision-making latency was shorter in large telencephalon guppy shoals, indicating that variation in telencephalon size can cause variation in the ability to avoid predation. This result is unlikely to be driven by differences in boldness, as several standard tests suggest that there is no difference in boldness between the telencephalon size selection lines. General aspects of shoaling dynamics did not differ between the telencephalon size selected lines. Our study highlights that rapid mosaic changes in brain region size may be an important mechanism behind social behavioural variation with strong fitness implications.

Although many animal species are known to learn to respond to human verbal commands, this ability is understudied, as are the cues used to do so. For the best-studied species, the dog, domestication itself is used to justify successful attending to human communicative cues. However, the role of domestication in sensitivity to human cues remains debated. Corvids are songbirds that engage in complex communicative behaviors with conspecifics and with other species. Rooks (Corvus frugilegus) are a cognitively complex, undomesticated corvid shown to possess complex vocal behaviors, and to learn to follow human gaze and pointing cues. Leonidas (Leo), an adult rook, began following verbal commands during unrelated studies, and was tested to confirm his command proficiency and to examine what part(s) of the signal he was using. Leo learned to perform three verbal commands correctly, and was primarily attending to the auditory components of the commands. He showed no evidence of using gaze or any subconscious cues from the experimenter, and though he did initially attend to lip movements, he rapidly overcame their absence. Two additional rooks could only be tested for a shorter duration, but also showed learning of commands, and reached proficiency in some. The ability of this undomesticated non-mammalian species to learn human verbal commands joins existing evidence that neither domestication nor extensive enculturation are strictly necessary for use of heterospecific human cues: instead, some species may be able to co-opt other complex cognitive abilities, possibly the same ones required for their complex communication, to achieve this.

Parids are well-known birds both in Europe and North America. Despite being arboreal foragers of similar size, there is a striking dichotomy in the wintering strategies in the family. Most species are food hoarding specialists that store large amounts of winter food in autumn. A small stable group will then defend a large winter territory in which they store food. From a cognition perspective these species are spatial memory specialists with the volume of the hippocampus, a brain structure that is important for spatial memorization, correlating to the degree of specialisation for food hoarding. The wintering strategy in non-hoarding parids, the Eurasian great and blue tits, and species that are closely related to these, is very different. They are generalist foragers that have adapted especially well to anthropogenic habitats such as gardens and city parks. The great tit stands out as being especially innovative and good at observational learning, deserving its reputation as being “smartest among tits”. As the great and blue tits do not occur in North America it is possible that some chickadee populations have adapted to anthropogenic habitats as opposed to their Eurasian close relatives. The black-capped chickadee, for example, has been observed mastering foraging techniques that only the great tit does in Europe. In conclusion, there is a trade-off between two cognitive specialisations in the family with hoarding parids being spatial memory specialists and non-hoarding innovative problem solvers. The starkness of this dichotomy probably depends on that the selection for optimal foraging in winter is especially strong in small birds.

One of the executive functions, inhibitory control, enables animals to suppress ineffective behaviors and facilitate flexible behavior. Seabirds, particularly those of the family Laridae, exploit diverse food resources across various environments. This suggests a possible link between their foraging behavior and inhibitory control. However, to date, inhibitory control in seabirds has not been assessed. We used a cylinder task to assess inhibitory control in wild black-tailed gulls, which are highly omnivorous seabirds. The task required gulls to suppress the dominant response of pecking at food inside a transparent cylinder, detour to the side openings, and retrieve the food without pecking the cylinder. The trial was considered successful if the gull retrieved the food without pecking the cylinder. Ten of the 12 individuals succeeded in the task within 10 trials, with their success rates improving across trials. These findings suggest that black-tailed gulls exhibit moderate levels of inhibitory control among birds and may learn detouring behavior through repetition.

Many communicative systems have been selected for efficiency, shaped by the trade-off between information transmission and energetic or temporal constraints. Linguistic laws such as Menzerath’s law—predicting shorter elements in longer sequences—have emerged as widespread principles across vocal communication in many species. While these laws have been predominantly studied at the species level, the influence of individual and social factors remain underexplored. In this study, we investigated adherence to Menzerath’s law in the vocal communication of carrion crows, Corvus corone corone, hooded crows, Corvus corone cornix and hybrids. Our findings show that crow call sequences adhere to Menzerath’s law, with shorter calls occurring in longer sequences, demonstrating structural efficiency in vocal communication. In carrion crows specifically, we analysed call sequences in relation to individual characteristics (sex, age) and social variables (group size, dominance status, strength of affiliative relationships). Interestingly, adherence to Menzerath’s law was stronger in females and younger individuals, while no effects were found for group size, dominance, or affiliative relationships. This study provides the first evidence of Menzerath’s law in corvid vocal communication and suggests that individual-level traits, rather than broader social dynamics, may shape vocal efficiency. These findings broaden our understanding of widespread principles in animal communication and raise new questions about the ontogeny and flexibility of vocal efficiency in complex social species.

A recent proposal defines prosociality in terms of intentional behaviour that successfully benefits another. We suggest, however, that prosociality would be better defined more simply in terms of the intention to benefit another, regardless of whether a benefit really occurs, for three reasons: (i) the construct of “benefit” is itself difficult to operationalize, (ii) an intention-based definition is no less conservative than the proposed outcome-based one, and (iii) an outcome-based definition overlooks plausible cases of intended but unsuccessful prosocial actions as well as the psychological consequences of such actions. Amending the working definition of prosociality to be centred on intentions, not outcomes, would make it more useful as a tool for comparative and developmental research.