Referential antipredator calls in the Siberian jay (Perisoreus infaustus) depend on predator behaviour (original) (raw)
Related papers
Referential calls signal predator behavior in a group-living bird species
Current Biology, 2008
Predation is a powerful agent of natural selection, driving the evolution of antipredator calls [1]. These calls have been shown to communicate predator category and/or predator distance to conspecifics . However, the risk posed by predators depends also on predator behavior , and the ability of prey to communicate predator behavior to conspecifics would be a selective advantage reducing their predation risk. I tested this idea in Siberian jays (Perisoreus infaustus), a group-living bird species. Predation by hawks, and to a lesser extent by owls, is substantial and the sole cause of mortality in adult jays . By using field data and predator-exposure experiments, I show here that jays used antipredator calls for hawks depending on predator behavior. A playback experiment demonstrated that these prey-to-prey calls were specific to hawk behavior (perch, prey search, attack) and elicited distinct, situation-specific escape responses. This is the first study to demonstrate that prey signals convey information about predator behavior to conspecifics. Given that antipredator calls in jays aim at protecting kin group members , consequently lowering their mortality [9], kin-selected benefits could be an important factor for the evolution of predator-behavior-specific antipredator calls in such systems.
Responses of Blue Jays (Cyanocitta cristata) to raptors that differ in predatory threat
Avian Biology Research
Some species of birds use their vocalisations to communicate predator presence and the level of threat they pose, including two species of corvids (Corvidae), American Crows (Corvus brachyrhynchos) and Siberian Jays (Perisoreus infaustus). Our objective was to determine if Blue Jays (Cyanocitta cristata), another corvid, also use specific calls or vary the characteristics of certain calls to convey information about the level of threat posed by aerial predators. During the non-breeding seasons of 2014 and 2015, we recorded and analysed the vocal responses of Blue Jays to study skins of six species of raptors that varied in size and the level of threat they pose to Blue Jays. Experiments were conducted at seven locations in Madison County, Kentucky. The mean number of Blue Jays present during trials was 2.6, and Blue Jays uttered five different vocalisations during trials, with ditonal and monotonal jeers given most frequently. The rate at which Blue Jays uttered ditonal jeers differ...
Nepotistic alarm calling in the Siberian jay, Perisoreus infaustus
Animal behaviour, 2004
From a life history perspective, parents have an incentive to protect their reproductive investment, and so may provide care even after their offspring are independent. Such prolonged parental care could lead to postponed dispersal of the offspring and thereby facilitate the formation of kin groups. We tested whether alpha birds in Siberian jays protected their independent, retained offspring by giving alarm calls during simulated predator attacks. We compared the responses to predator attacks simulated by flying a hawk model over a dyad of birds on a feeder for dyads composed of an alpha bird and either a relative or a nonrelative. Alpha females were nepotistic in their alarm-calling behaviour, in that they called more frequently when accompanied by their retained offspring than by unrelated immigrants, but alpha males called indiscriminately. This difference in alarm calling could reflect dominance relationships in Siberian jay groups, because the presence of immigrants may be less costly to alpha males, but alpha females are more vulnerable to competition from immigrants. Alarm calls were usually given during escape, when both individuals in the dyad had left the feeding site. However, results of a playback experiment suggest that alarm calls conveyed information about danger and incited an immediate escape reaction. Our results indicate that alarm calling can be nepotistic, and that factors other than kinship influence alarm-calling behaviour. Nepotistic antipredator behaviours are benefits that offspring can gain only in their natal territory. Hence, in the absence of preferential treatment by their parents, offspring may be more likely to disperse and kin groups are prevented from forming.
Predation risk induces changes in nest-site selection and clutch size in the Siberian jay
… of the Royal …, 2006
Life-history theory predicts that an individual should reduce its reproductive efforts by laying a smaller clutch size when high risk of nest predation reduces the value of current reproduction. Evidence in favour of this ‘nest predation hypothesis’, however, is scarce and based largely on correlative analyses. Here, we manipulated perceived risk of nest predation in the Siberian jay Perisoreus infaustus using playback involving a mixture of calls by corvid nest predators in the vicinity of nest sites. In response to being exposed to this acoustic cue simulating increased risk of nest predation, the jays chose a nest site offering more protective covering and reduced clutch size. This is the first experimental demonstration of clutch size adjustment and nest site selection as a result of phenotypic plasticity in an open nesting passerine reflecting a facultative response to the perceived risk of nest predation.
Mobbing calls signal predator category in a kin group-living bird species
Proceedings of the Royal Society B: …, 2009
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.
Defence behaviour against brood parasitism is deeply rooted in mainland and island scrub-jays
Animal Behaviour, 2007
When selection pressures for an adaptation relax, the trait may decline, or it may be maintained if there are no fitness costs. The interactions between avian brood parasites and their hosts are dynamic, with selection pressures changing as host or parasite ranges shift, or as parasites switch to new hosts once old hosts evolve defences. The extent to which hosts retain defences in the absence of parasites has important consequences to parasiteehost coevolution. We tested whether island scrub-jays, Aphelocoma insularis, and western scrub-jays, A. californica, have maintained egg ejection behaviour in the absence of brood parasitism and provide an estimate of how long they have maintained ejection. Island scrub-jays and western scrub-jays ejected 100% of foreign eggs placed into their nests, and genetic analyses revealed no evidence of conspecific brood parasitism that could maintain ejection. Extreme variation in intraclutch egg appearance may result in hosts ejecting their own oddly coloured eggs, which would select against the maintenance of ejection. However, island, western and Florida scrub-jays, A. coerulescens, also an ejecter, showed less variation than the common grackle, Quiscalus quiscula, a species that has an extremely high level of intraclutch egg variation and may have lost its rejection defence, because it rejects its own oddly coloured eggs. Based on molecular clock analyses of mitochondrial DNA control region and ND2 sequences, island and western scrub-jays split approximately 140 000e151 000 years ago, western and Florida scrub-jays 1 000 000 years ago, and island and Florida scrub-jays 1 250 000 years ago. Ejection behaviour may have been maintained this long in the absence of parasitism, but it is possible that scrub-jays were parasitized as recently as the end of the Pleistocene 10 000 years ago, when cowbirds were more abundant. Nevertheless, these results indicate that (1) egg ejection is not a costly trait to maintain in scrub-jays, (2) brood parasites may not be able to alternate between well-defended hosts and hosts that have lost ejection defence following past episodes of parasitism and (3) brood parasites may have to deal with host communities that have well-developed defences by evolving specialized adaptations for a single host species or a small set of species.
Predator-induced plasticity in nest visitation rates in the Siberian jay (Perisoreus infaustus)
Behavioral Ecology, 2005
Bird nestlings may be at risk not only from starvation but also from predators attracted to the nest by parental feeding visits. Hence, parents could trade reduced visitation rates for a lower predation risk. Here, through field data and an experiment, we show plasticity in daily patterns of nest visitation in the Siberian jay, Perisoreus infaustus, in response to predator activity. In highrisk territories, jay parents avoided going to the nest at certain times of the day and compensated by allocating more feeding effort to periods when predators were less active. Such modifications in provisioning routines allowed parents in high-risk habitat to significantly lower the risk of providing visitation cues to visually oriented corvid nest predators. These results indicate that some birds modify their daily nest visitation patterns as a fourth mechanism to reduce predator-attracting nest visits in addition to the clutch size reduction, maximization of food load-sizes, and prevention of allofeeding suggested by Skutch.
Proceedings of the Royal Society B
Food-storing corvids use many cache-protection and pilfering strategies. We tested whether Eurasian jays (Garrulus glandarius) reduce the transfer of auditory information to a competitor when caching and pilfering. We gave jays a noisy and a quiet substrate to cache in. Compared with when alone, birds cached less in the noisy substrate when with a conspecific that could hear but could not see them caching. By contrast, jays did not change the amount cached in the noisy substrate when they were with a competitor that could see and hear them caching compared with when they were alone. Together, these results suggest that jays reduce auditory information during caching as a cache-protection strategy. By contrast, as pilferers, jays did not attempt to conceal their presence from a cacher and did not prefer a silent viewing perch over a noisy one when observing caching. However, birds vocalized less when watching caching compared with when they were alone, when they were watching a non-caching conspecific or when they were watching their own caches being pilfered. Pilfering jays may therefore attempt to suppress some types of auditory information. Our results raise the possibility that jays both understand and can attribute auditory perception to another individual.