Naive Juveniles Are More Likely to Become Breeders after Witnessing Predator Mobbing

Abstract

Dryad data: http://dx.doi.org/10.5061/dryad.50m10.abstract: Responding appropriately during the first predatory attack in life is often critical for survival. In many social species, naive juveniles acquire this skill from conspecifics, but its fitness consequences remain virtually unknown. Here we experimentally demonstrate how naive juvenile Siberian jays (Perisoreus infaustus) derive a long-term fitness benefit from witnessing knowledgeable adults mobbing their principal predator, the goshawk (Accipiter gentilis). Siberian jays live in family groups of two to six individuals that also can include unrelated nonbreeders. Field observations showed that Siberian jays encounter predators only rarely, and, indeed, naive juveniles do not respond to predator models when on their own but do when observing other individuals mobbing them. Predator exposure experiments demonstrated that naive juveniles had a substantially higher first-winter survival after observing knowledgeable group members mobbing a goshawk model, increasing their likelihood of acquiring a breeding position later in life. Previous research showed that naive individuals may learn from others how to respond to predators, care for offspring, or choose mates, generally assuming that social learning has long-term fitness consequences without empirical evidence. Our results demonstrate a long-term fitness benefit of vertical social learning for naive individuals in the wild, emphasizing its evolutionary importance in animals, including humans.

Family living sets the stage for cooperative breeding and ecological resilience in birds

“…For example, family living can reduce the mortality of independent juveniles [38] through parental protection against predators [39–41], easier offspring access to resources [42,43], increased offspring foraging efficiency [44], and a potential reduction of per capita investment in territoriality [45]. Furthermore, family living is associated with ample opportunities to socially acquire critical life skills [46] and potentially increase cognitive abilities [47]. These benefits of family life may improve offspring survival in productive but variable environments [38] and lead to higher grand-offspring fitness even in the absence of helping at the nest [48].…”

Largemouth bass use prior experience, but not information from experienced conspecifics, to avoid capture by anglers

“…For example, both zebrafish, Danio rerio (Hamilton), and guppies placed into aquaria with conspecifics that were experienced with a simulated trawl net were able to socially learn from experienced individuals to escape capture (Brown & Laland, ; Lindeyer & Reader, ). Social learning from experienced conspecifics has also facilitated the identification of predator cues in several taxa, including amphibians (Chivers & Ferrari, ), birds (Griesser & Suzuki, ) and fish (Manassa & McCormick, ; Vilhunen et al, ). Despite these previous results, no evidence was found that largemouth bass socially learned via observational conditioning to avoid fishing lures.…”

“…Learning is essential for survival, as organisms must glean information from their environment to forage successfully, attract mates and avoid predators (Brown & Laland, 2003;Lima & Dill, 1990). The ability to learn is therefore linked to fitness outcomes whereby individuals that successfully acquire and incorporate new information into behavioural decisions will likely experience greater fitness (Griesser & Suzuki, 2017;Manassa & McCormick, 2013;Sih & Del Giudice, 2012). This need to acquire and process information is also important in environments altered by human activities, including the destruction of habitat, hunting and fishing, pollution, or the introduction of non-native species (Sih, 2013).…”

Experience buffers extrinsic mortality in a group‐living bird species

“…Juveniles do not respond to hawk models when exposed to them in absence of older individuals (Griesser and Suzuki ), and during simulated hawk attacks, juveniles have a longer reaction time than breeders (Griesser ). However, all juveniles that observe knowledgeable group members mobbing a goshawk model survived their first winter (Griesser and Suzuki ). These findings support the notion that the high juvenile mortality reflects a lack of antipredator skills.…”

“…Yet, individuals in species that regularly encounter predators on their own have a high risk of being killed, making individual learning difficult (van Schaik ). Group living can directly provide safety in numbers (Caro ) but may also provide inexperienced individuals with a safe haven to acquire critical life‐skills (van Schaik and Burkart , Loukola et al , Griesser and Suzuki ). Finally, living in habitats that provide protection from predators can buffer the predation risk of inexperienced individuals, which may explain the accelerated population declines of many species living in managed habitats, not only in the tropics but also in boreal forests (Monkkonen , Eggers and Low , Virkkala ).…”