| 1. |
- Mills, James A., et al.
(författare)
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Archiving Primary Data : Solutions for Long-Term Studies
- 2015
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Ingår i: Trends in Ecology & Evolution. - : Elsevier BV. - 0169-5347 .- 1872-8383. ; 30:10, s. 581-589
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Tidskriftsartikel (refereegranskat)abstract
- The recent trend for journals to require open access to primary data included in publications has been embraced by many biologists, but has caused apprehension amongst researchers engaged in long-term ecological and evolutionary studies. A worldwide survey of 73 principal investigators (PIs) with long-term studies revealed positive attitudes towards sharing data with the agreement or involvement of the PI, and 93% of PIs have historically shared data. Only 8% were in favor of uncontrolled, open access to primary data while 63% expressed serious concern. We present here their viewpoint on an issue that can have non-trivial scientific consequences. We discuss potential costs of public data archiving and provide possible solutions to meet the needs of journals and researchers.
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| 2. |
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| 3. |
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| 4. |
- Barnaby, Jonathan, 1965-, et al.
(författare)
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The role of nepotism, cooperation, and competition in the avian families
- 2010
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Bok (refereegranskat)abstract
- A large number of bird species live in stable groups, and this sets the scene for complex social behaviours, such as cooperative breeding. The vast majority of groups consist of families which arise when young postpone dispersal and remain with their parents beyond independence. However, the factors selecting for the evolution of families and thus also cooperative breeding among birds, are still a challenging puzzle. The currently accepted key explanation for the evolution of families and cooperative breeding focuses on dispersal constraints. While constraints successfully explain within‐population dispersal decisions, they fail as an ultimate explanation because offspring in the majority of species face some sort of dispersal constraint, yet still disperse promptly. Recent alternative explanations focus on the role of philopatry and nepotism, and emphasise a key role of life‐history for the evolution of families. Phylogenetic analyses and field studies have indicated that living in family groups is far more widespread among long‐lived species than short‐lived ones. A long lifespan gives parents the opportunity to invest in their offspring for a prolonged period, while this option is less viable for short‐lived species. Thus, living with nepotistic parents provides offspring with direct fitness benefits that can select for the evolution of family living beyond independence. Nevertheless this generalisation is brought into question since many long‐lived bird species do not live in family groups. An alternative approach attempts to explain family living through the variation in territory quality. Here the incentive to remain with the parents is created by the availability of resources on the natal territory independent of parental nepotism. However, there is not only cooperation, conflicts are also common place in families. Living with independent, sexually mature offspring can lead to conflicts through a change in resource availability or the death of aparent. Therefore families can be expected to be dynamic societies where both parent and offspring decisions depend on each other, and family maintenance depends upon the current ecological conditions. Based on this background, here we review recent studies that have investigated the processes that facilitate family formation, and which highlight both cooperation and conflict that arises from living in family groups. We examine the strengths of current models and explore ideas for a more coherent framework in which to understand prolonged family association in birds. We argue that two paths lead to family living, depending on the life-history. In medium-short lived species where the postponement of independent reproduction comes at a high cost, offspring can benefit from an association with their parents until the next breeding season. In longer-lived species, offspring actually benefit from postponing the onset of independent reproduction, making family living beyond the first year of life an adaptive strategy, and giving the option for cooperative breeding. These processes are illustrated by 5 species-specific case studies. We then finally suggest a number of key questions to developing a deeper understanding of the evolution of family living in birds.
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| 5. |
- Bliard, Louis, et al.
(författare)
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Family living and cooperative breeding in birds are associated with the number of avian predators
- 2024
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Ingår i: EVOLUTION. - 0014-3820 .- 1558-5646.
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Tidskriftsartikel (refereegranskat)abstract
- Cooperative breeding occurs when individuals contribute parental care to offspring that are not their own. Numerous intra- and interspecific studies have aimed to explain the evolution of this behavior. Recent comparative work suggests that family living (i.e., when offspring remain with their parents beyond independence) is a critical stepping stone in the evolution of cooperative breeding. Thus, it is key to understand the factors that facilitate the evolution of family living. Within-species studies suggest that protection from predators is a critical function of group living, through both passive benefits such as dilution effects and active benefits such as prosocial antipredator behaviors in family groups. However, the association between predation risk and the formation and prevalence of family groups and cooperative breeding remains untested globally. Here, we use phylogenetic comparative analyses including 2,984 bird species to show that family living and cooperative breeding are associated with increased occurrence of avian predators. These cross-species findings lend support to previous suggestions based on intraspecific studies that social benefits of family living, such as protection against predation, could favor the evolution of delayed dispersal and cooperative breeding.
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| 6. |
- Covas, R, et al.
(författare)
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Life history and the evolution of family living in birds
- 2007
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 274:1616, s. 1349-1357
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Forskningsöversikt (refereegranskat)abstract
- The reason why some bird species live in family groups is an important question of evolutionary biology that remains unanswered. Families arise when young delay the onset of independent reproduction and remain with their parents beyond independence. Explanations for why individuals forgo independent reproduction have hitherto focused on dispersal constraints, such as the absence of high-quality breeding openings. However, while constraints successfully explain within-population dispersal decisions, they fail as an ultimate explanation for variation in family formation across species. Most family-living species are long-lived and recent life-history studies demonstrated that a delayed onset of reproduction can be adaptive in long-lived species. Hence, delayed dispersal and reproduction might be an adaptive life-history decision rather than ‘the best of a bad job’. Here, we attempt to provide a predictive framework for the evolution of families by integrating life-history theory into family formation theory. We suggest that longevity favours a delayed onset of reproduction and gives parents the opportunity of a prolonged investment in offspring, an option which is not available for short-lived species. Yet, parents should only prolong their investment in offspring if this increases offspring survival and outweighs the fitness cost that parents incur, which is only possible under ecological conditions, such as a predictable access to resources. We therefore propose that both life-history and ecological factors play a role in determining the evolution of family living across species, yet we suggest different mechanisms than those proposed by previous models.
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| 7. |
- Cunha, Filipe C. R., et al.
(författare)
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Who do you trust? : Wild birds use social knowledge to avoid being deceived
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:22
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Tidskriftsartikel (refereegranskat)abstract
- Many species give deceptive warning calls, enabled by the high risk of ignoring them. In Siberian jays, a territorial, group-living bird, individuals give warning calls toward perched predators and mob them. However, intruding neighbors can emit these warning calls in the absence of predators to access food, but breeders often ignore these calls. Playback field experiments show that breeders flee sooner and return later after warning calls of former group members than those of neighbors or unknown individuals. Thus, breeders respond appropriately only to warning calls of previous cooperation partners. This mechanism facilitates the evolution and maintenance of communication vulnerable to deceptive signaling. This conclusion also applies to human language because of its cooperative nature and thus, its vulnerability to deception.
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| 8. |
- Dufour, Paul, 1992, et al.
(författare)
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The importance of migratory drop-off for island colonization in birds
- 2024
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Ingår i: PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES. - 0962-8452 .- 1471-2954. ; 291:2021
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Tidskriftsartikel (refereegranskat)abstract
- Seasonal migration is an underappreciated driver of animal diversification. Changes in migratory behaviour may favour the establishment of sedentary founder populations and promote speciation if there is sufficient reproductive isolation between sedentary and migratory populations. From a systematic literature review, we here quantify the role of migratory drop-off-the loss of migratory behaviour-in promoting speciation in birds on islands. We identify at least 157 independent colonization events likely initiated by migratory species that led to speciation, including 44 cases among recently extinct species. By comparing, for all islands, the proportion of island endemic species that derived from migratory drop-off with the proportion of migratory species among potential colonizers, we showed that seasonal migration has a larger effect on island endemic richness than direct dispersal. We also found that the role of migration in island colonization increases with the geographic isolation of islands. Furthermore, the success of speciation events depends in part on species biogeographic and ecological factors, here positively associated with greater range size and larger flock sizes. These results highlight the importance of shifts in migratory behaviour in the speciation process and calls for greater consideration of migratory drop-off in the biogeographic distribution of birds.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Eggers, Sonke, et al.
(författare)
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Predator-induced reductions in nest visitation rates are modified by forest cover and food availability
- 2008
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 19:5, s. 1056-1062
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Tidskriftsartikel (refereegranskat)abstract
- Bird parents can alert predators to the location of their nest. One mitigating option is that parents reduce their nest visitation rate in exchange for a lower predation risk. Here, using field data and experiments, we show that Siberian jay Perisoreus infaustus parents adjust feeding visit rates depending on an interaction of 3 factors: predator activity, nest concealment, and food availability. The rate of nest visits increased with the degree of nest concealment; yet, this relationship was modified by the presence of corvid predators. As the vegetation became more dense, parents at sites with high corvid activity disproportionately increased their feeding visit rates when compared with birds at sites with low corvid activity. We experimentally assessed how nesting cover affects this response of parents to the presence of corvids by using an Eurasian jay Garrulus glandarius model. Parents nesting at open sites ceased nest visits, whereas those nesting in dense forest continued feeding, albeit at a lower rate. Cover may thus not fully compensate for the effect of predator activity on feeding visit rates. However, offspring exposed to high predator activity might still receive the same amount of food because parents may adjust load sizes to compensate. This idea was confirmed by an experiment showing that in areas of high predator activity, food-supplemented birds significantly decreased nest visits when compared with nonsupplemented birds. These results indicate that some bird species can employ multiple nest-defense strategies to reduce predator-attracting nest visits; yet, these strategies may carry fitness consequences through reduced offspring quality.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Griesser, Michael, et al.
(författare)
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Causes of Ring-Related Leg Injuries in Birds – Evidence and Recommendations from Four Field Studies
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- One of the main techniques for recognizing individuals in avian field research is marking birds with plastic and metal leg rings. However, in some species individuals may react negatively to rings, causing leg injuries and, in extreme cases, the loss of a foot or limb. Here, we report problems that arise from ringing and illustrate solutions based on field data from Brown Thornbills (Acanthiza pusilla) (2 populations), Siberian Jays (Perisoreus infaustus) and Purple-crowned Fairy-wrens (Malurus coronatus). We encountered three problems caused by plastic rings: inflammations triggered by material accumulating under the ring (Purple-crowned Fairy-wrens), contact inflammations as a consequence of plastic rings touching the foot or tibio-tarsal joint (Brown Thornbills), and toes or the foot getting trapped in partly unwrapped flat-band colour rings (Siberian Jays). Metal rings caused two problems: the edges of aluminium rings bent inwards if mounted on top of each other (Brown Thornbills), and too small a ring size led to inflammation (Purple-crowned Fairy-wrens). We overcame these problems by changing the ringing technique (using different ring types or larger rings), or using different adhesive. Additionally, we developed and tested a novel, simple technique of gluing plastic rings onto metal rings in Brown Thornbills. A review of studies reporting ring injuries (N = 23) showed that small birds (<55 g body weight) are more prone to leg infections while larger birds (>35 g) tend to get rings stuck over their feet. We give methodological advice on how these problems can be avoided, and suggest a ringing hazard index to compare the impact of ringing in terms of injury on different bird species. Finally, to facilitate improvements in ringing techniques, we encourage online deposition of information regarding ringing injuries of birds at a website hosted by the European Union for Bird Ringing (EURING).
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| 17. |
- Griesser, Michael
(författare)
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Dark or Short Nights: Differential Latitudinal Constraints in Nestling Provisioning Patterns of a Nocturnally Hunting Bird Species
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- In diurnal bird species, individuals breeding at high latitudes have larger broods than at lower latitudes, which has been linked to differences in the daily time available for foraging. However, it remains unclear how latitude is linked with parental investment in nocturnal species. Here, we investigate nestling provisioning rates of male Tengmalm's owls in two populations at different latitudes (Czech Republic 50 degrees N; Finland 63 degrees N) with the help of cameras integrated into nest boxes. Clutch sizes were smaller in the Czech population (CZ: 5.1+/-0.1; FIN: 6.6+/-0.1), but given the higher nestling mortality in the Finnish population, the number of fledglings did not differ between the two populations (CZ: 3.5+/-0.3; FIN: 3.9+/-0.2). Nestling provisioning patterns varied within days, over the reproductive season and between the two sites. Males delivered most food at dusk and dawn, having peak delivery rates at sun angles of -11 degrees to -15 degrees at both sites, and males increased the prey delivery rates with higher nestling requirements. Given the longer nights during summer in the Czech Republic compared to Finland, Czech males only showed a small shift in their delivery peak during the night from -17 degrees in April to -14 degrees in July. In contrast, Finnish males shifted their peak of prey delivery from -11 degrees in April to -1 degrees in July. Consequently, Czech males had a longer hunting time per night around midsummer when feeding young (360 min) than Finnish males (270 min). This suggests that nocturnal owl species in northern populations are constrained by the short nights during the breeding season, which can limit the number of young they can raise. Moreover, owls in northern populations are additionally constrained through the unpredictable changes in food availability between years, and both these factors are likely to influence the reproductive investment between populations.
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| 18. |
- Griesser, Michael, et al.
(författare)
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Experience buffers extrinsic mortality in a group-living bird species
- 2017
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 126:9, s. 1258-1268
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Tidskriftsartikel (refereegranskat)abstract
- Extrinsic mortality has a strong impact on the evolution of life-histories, prey morphology and behavioural adaptations, but for many animals the causes of mortality are poorly understood. Predation is an important driver of extrinsic mortality and mobile animals form groups in response to increased predation risk. Furthermore, in many species juveniles suffer higher mortality than older individuals, which may reflect a lower phenotypic quality, lower competitiveness, or a lack of antipredator or foraging skills. Here we assessed the causes of mortality for 371 radio tagged Siberian jays. This sedentary bird species lives in family groups that contain a breeding pair as well as related and unrelated non-breeders. Ninety-five percent of death were due to predation (n = 59 out of 62 individuals) and most individuals were killed by Accipiter hawks. Multivariate Cox proportional hazards models showed that non-breeders had a lower survival than breeders, but only in territories in managed forest with little visual cover. Examining breeders, only sex influenced survival with males having a lower survival than females. For non-breeders, juveniles had lower survival than older non-breeders, and those on managed territories had lower survival than those on unmanaged territories. Additionally, a low feather quality reduced the survival probability of non-breeders only. Thus, living on managed territories and having a low feature quality affected only non-breeders, particularly juveniles. These findings add to previous research demonstrating that juvenile Siberian jays acquire critical antipredator skills from experienced group members. Thus, experience can buffer extrinsic mortality, highlighting that group living not only provides safety in numbers, but also provide social opportunities to learn critical life-skills.
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| 19. |
- Griesser, Michael
(författare)
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Family living sets the stage for cooperative breeding and ecological resilience in birds
- 2017
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Ingår i: PLoS Biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Cooperative breeding is an extreme form of cooperation that evolved in a range of lineages, including arthropods, fish, birds, and mammals. Although cooperative breeding in birds is widespread and well-studied, the conditions that favored its evolution are still unclear. Based on phylogenetic comparative analyses on 3,005 bird species, we demonstrate here that family living acted as an essential stepping stone in the evolution of cooperative breeding in the vast majority of species. First, families formed by prolonging parent-offspring associations beyond nutritional independency, and second, retained offspring began helping at the nest. These findings suggest that assessment of the conditions that favor the evolution of cooperative breeding can be confounded if this process is not considered to include 2 steps. Specifically, phylogenetic linear mixed models show that the formation of families was associated with more productive and seasonal environments, where prolonged parent-offspring associations are likely to be less costly. However, our data show that the subsequent evolution of cooperative breeding was instead linked to environments with variable productivity, where helpers at the nest can buffer reproductive failure in harsh years. The proposed 2-step framework helps resolve current disagreements about the role of environmental forces in the evolution of cooperative breeding and better explains the geographic distribution of this trait. Many geographic hotspots of cooperative breeding have experienced a historical decline in productivity, suggesting that a higher proportion of family-living species could have been able to avoid extinction under harshening conditions through the evolution of cooperative breeding. These findings underscore the importance of considering the potentially different factors that drive different steps in the evolution of complex adaptations.
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| 20. |
- Griesser, Michael, et al.
(författare)
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Fine-scale kin recognition in the absence of social familiarity in the Siberian jay, a monogamous bird species
- 2015
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 24:22, s. 5726-5738
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Tidskriftsartikel (refereegranskat)abstract
- Kin recognition is a critical element to kin cooperation, and in vertebrates, it is primarily based on associative learning. Recognition of socially unfamiliar kin occurs rarely, and it is reported only in vertebrate species where promiscuity prevents recognition of first-order relatives. However, it is unknown whether the recognition of socially unfamiliar kin can evolve in monogamous species. Here, we investigate whether genetic relatedness modulates aggression among group members in Siberian jays (Perisoreus infaustus). This bird species is genetically and socially monogamous and lives in groups that are formed through the retention of offspring beyond independence, and the immigration of socially unfamiliar nonbreeders. Observations on feeders showed that genetic relatedness modulated aggression of breeders towards immigrants in a graded manner, in that they chased most intensely the immigrant group members that were genetically the least related. However, cross-fostering experiments showed that breeders were equally tolerant towards their own and cross-fostered young swapped as nestlings. Thus, breeders seem to use different mechanisms to recognize socially unfamiliar individuals and own offspring. As Siberian jays show a high degree of nepotism during foraging and predator encounters, inclusive fitness benefits may play a role for the evolution of fine-scale kin recognition. More generally, our results suggest that fine-graded kin recognition can evolve independently of social familiarity, highlighting the evolutionary importance of kin recognition for social species.
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| 21. |
- Griesser, Michael, et al.
(författare)
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From bird calls to human language : exploring the evolutionary drivers of compositional syntax
- 2018
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Ingår i: Current Opinion in Behavioral Sciences. - : Elsevier. - 2352-1546 .- 2352-1554. ; 21, s. 6-12
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Forskningsöversikt (refereegranskat)abstract
- Compositional syntax, where lexical items are combined into larger units, has been assumed to be unique to human language. Recent experiments, however, showed that Japanese tits combine alert and recruitment calls into alert-recruitment sequences when attracting conspecifics to join in mobbing a predator. We speculate that such call combinations are favoured when: Firstly, callers and receivers have shared interests in exchanging information; secondly, species produce different types of calls in different situations, leading to distinct behavioural responses in receivers; and finally, complex situations exist in which receivers benefit by combining two or more behaviours. These preconditions were also present in human ancestors. Thus, future work on bird calls may provide insights into the evolution of compositional syntax in human language.
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| 22. |
- Griesser, Michael, et al.
(författare)
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Impact of forestry practices on fitness correlates and population productivity in an open-nesting bird species
- 2007
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Ingår i: Conservation Biology. - : Wiley. - 0888-8892 .- 1523-1739. ; 21:3, s. 767-774
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Tidskriftsartikel (refereegranskat)abstract
- In the boreal forests of Fennoscandia, over 99% of forest area has been altered by forestry practices, which has created forest with age structures and stand characteristics that differ from primary forest stands. Although many researchers have investigated how forestry affects species abundance, few have assessed how forestry practices affect fitness correlates of species living in altered habitats, and this has negatively affected management efforts. We experimentally addressed the effect of standard forestry practices on fitness correlates of an open-nesting, long-lived bird species typical to boreal forests of Eurasia, the Siberian Jay (Perisoreus infaustus). We used a before-after comparison of reproductive data on the level of territories and found that standard forestry practices had a strong negative effect on the breeding success of jays. Both partial thinning of territories and partial clearcutting of territories reduced future breeding success by a factor of 0.35. Forestry practices reduced territory occupancy. Thus, over the 15 years of the study, productivity of the affected population declined over 50% as a result of territory abandonment and reduced breeding success. Results of previous studies on Siberian Jays suggest that the strong effect of forest thinning on fitness is explained by the fact that most common predators of nests and adults are visually oriented and thus thinning makes prey and nests more visible to predators. The consequences of thinning we observed are likely to apply to a wide range of species that rely on understory to provide visual protection from predators. Thus, our results are important for the development of effective conservation management protocols and for the refinement of thinning practices.
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| 23. |
- Griesser, Michael, et al.
(författare)
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Influence of Winter Ranging Behaviour on the Social Organization of a Cooperatively Breeding Bird Species, The Apostlebird
- 2009
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 115:9, s. 888-896
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Tidskriftsartikel (refereegranskat)abstract
- Most cooperative breeding bird species live in family groups that are formed through the prolonged association of offspring with their parents. Research into cooperative families has in particular investigated the balance between cooperation and conflict over reproductive decisions. As a consequence of this research focus, social interactions among group members outside the breeding season are rarely studied, despite the fact that they are likely to be crucial for social decisions. We investigated the social dynamics and ranging behaviour of the family group living cooperatively breeding apostlebird (Struthidea cinerea) outside the breeding season. Group size changed between, but not within, the seasons, being smaller during the breeding season than in the winter season. This change in group size was a consequence of breeding groups merging after breeding, then splitting again before the next breeding season. While breeding groups used small, non-overlapping home ranges (x = 113 ha) around the nesting site, during winter groups moved up to 1200 ha (x = 598 ha), and interacted frequently with up to four other winter groups. In particular large groups often joined together during winter and spent up to 50% of their time associating with other large winter groups. This apparent fission-fusion system facilitated the exchange of group members, offering the possibility to form new breeding coalitions and new groups. The results of this study suggest that behaviour outside the breeding season can be of considerable importance to the social dynamics of both families and cooperative breeding in such systems.
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| 24. |
- Griesser, Michael, et al.
(författare)
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Long-term effects of forest management on territory occupancy and breeding success of an open-nesting boreal bird species, the Siberian jay
- 2012
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 271, s. 58-64
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Tidskriftsartikel (refereegranskat)abstract
- In large parts of the world forests are intensively managed, affecting stand structure and biodiversity. Since re-growth of trees can be slow and management cycles can span over 100 years, long-term longitudinal data are needed to assess the effects of forestry on organisms living in these habitats. Here, we draw upon 50 years of population data of an open-nesting, sedentary bird species, typically of boreal forests, the Siberian jay (Perisoreus infaustus). Forests at the study site were managed by clear-cutting and re-plantation, and a management cycle spanning over 120 years. We tracked changes in forest structure in the nest vicinity and the whole territory with the help of aerial images, and linked them to territory occupancy and offspring production in 13 territories. While territories were occupied in 77.2% of all instances, reproduction was only successful in 19.6% of all instances. Both parameters were positively influenced by a large proportion of unthinned forests older than 50 years, which provide visual protection from nest and adult predators. Thus, it is crucial to assess both territory occupancy and reproductive output to understand the effects of forestry on bird populations. Moreover, our results suggest that in forests with slow turnover cycles, management which avoids thinning (such as green tree retention forestry) can promote population persistence of open-nesting bird species.
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| 25. |
- Griesser, Michael
(författare)
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Mobbing calls signal predator category in a kin group-living bird species
- 2009
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 276:1669, s. 2887-2892
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Tidskriftsartikel (refereegranskat)abstract
- Many prey species gather together to approach and harass their predators despite the associated risks. While mobbing, prey usually utter calls and previous experiments have demonstrated that mobbing calls can convey information about risk to conspecifics. However, the risk posed by predators also differs between predator categories. The ability to communicate predator category would be adaptive because it would allow other mobbers to adjust their risk taking. I tested this idea in Siberian jays Perisoreus infaustus, a group-living bird species, by exposing jay groups to mounts of three hawk and three owl species of varying risks. Groups immediately approached to mob the mount and uttered up to 14 different call types. Jays gave more calls when mobbing a more dangerous predator and when in the presence of kin. Five call types were predator-category-specific and jays uttered two hawk-specific and three owl-specific call types. Thus, this is one of the first studies to demonstrate that mobbing calls can simultaneously encode information about both predator category and the risk posed by a predator. Since antipredator calls of Siberian jays are known to specifically aim at reducing the risk to relatives, kin-based sociality could be an important factor in facilitating the evolution of predator-category-specific mobbing calls.
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