Eavesdropping of an African ground squirrel on the heterospecific alarm calls of a noisy ground‐nesting bird

Abstract

Animals gather information about their environment from a variety of sources to enable adaptive decision-making behaviour. Eavesdropping on heterospecific alarm calls enhances predator avoidance, reduces time spent vigilant and allows for more time on daily activities such as foraging. If the information is relevant and reliable, individuals that respond to heterospecific signals may benefit from a wider range of information at a low marginal cost. The Cape ground squirrel (Xerus inauris) and crowned lapwing (Vanellus chilensis) are ground-dwelling species that are taxonomically distant but share similar predators, habitat and anti-predatory behaviours. We used playback experiments of the alarm calls produced by conspecifics and lapwings to investigate the vigilance responses of adult female Cape ground squirrels. Squirrels responded with greater vigilance to both squirrel and lapwing alarm calls, and no changes of vigilance levels were observed in response to a control sound. However, contrary to our predictions, changes in vigilance and time to relax did not differ between conspecific versus heterospecific playbacks. The results from our study suggest that squirrels perceive lapwing alarm calls as relevant and reliable information and that responding to it could increase their survival.

Bio-acoustic tracking and localization using heterogeneous, scalable microphone arrays

“…Larger arrays can also be used to study how songbirds alarm each other when predators are nearby 56 and how these alarm signals vary based on the predator 57 . Some species may even eavesdrop on the alarm signals to their own benefit 58 .…”

Behaviors associated with vocal communication of squirrels

“…Eavesdropping on the alarm calls of or foraging with other species may especially be beneficial to solitary species, territorial species, or species that live in dense habitat, such as tropical rain forests, where group vigilance from conspecifics is limited. However, Cape ground squirrels, who live in groups in arid grasslands, also respond to bird alarm calls (Waterman and Mai 2020), indicating behavioral responses to vocal signals from heterospecifics may be important for predator vigilance in multiple species of squirrels across different habitat types, even if they live colonially.…”