The role of learning, acoustic similarity and phylogenetic relatedness in the recognition of distress calls in birds

Many groups of vertebrates produce distress calls when attacked by predators as a last attempt to survive. However, few studies investigate whether recognition of distress calls involves learning or acoustic similarity to familiar calls. This study assesses the importance of these two factors as well as phylogenetic relatedness in distress call recognition by tropical rainforest birds. We measured the avian community responses to familiar and unfamiliar distress calls in a lowland tropical rainforest in Costa Rica using playbacks of a sympatric species, the orange-billed sparrow, Arremon aurantiirostris, and a closely related allopatric species, the white-eared ground-sparrow, Melozone leucotis. In addition, to test whether recognition is driven by phylogenetic relatedness to the call sender, we compared the phylogenetic distance of approaching individuals to A. aurantiirostris when using different playback stimuli. We found that individuals called back to sympatric and allopatric calls within similar amounts of time, supporting the role of acoustic similarity in distress call recognition. We also found that individuals approached faster and spent more time inside the observation zone for sympatric distress calls than for allopatric distress calls, and both responses were stronger than the response to white noise (control), which supports the roles of acoustic similarity and learning in distress call recognition. Sympatric distress calls elicited approaching reactions from species that were more closely related to the sympatric species than did white noise, which suggests that phylogenetically related species are more likely to identify and respond to the sympatric distress signaller, while white noise elicited responses from a random subset of species that were on average more distantly related to the sympatric signaller. We conclude that learning, acoustic similarity and phylogenetic relatedness play important roles in the response to distress calls.(c) 2021 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.