Western Australian magpies respond to urgency information contained in conspecific alarm calls

Abstract

Many animals provide information about predator proximity in their alarm calls. In response to predators further away, Western Australian magpies (Gymnorhina tibicen dorsalis) produce alarm calls containing fewer notes compared to those produced when predators are closer. Since the ability to make fine-scale adjustments to antipredator responses by being sensitive to the level of urgency in calls may be beneficial, receivers are expected to be able to appropriately decipher and respond to this information. We conducted playbacks to test whether magpies can respond to urgency information in conspecific alarm calls. Magpies were exposed to low-urgency calls (calls with one note), high-urgency calls (calls with four notes), and one- and four-note control calls. Receivers showed greater levels of responsiveness following playbacks of high-urgency calls compared to playbacks of low-urgency and control calls, providing evidence that magpies can respond to information about the urgency of a predator threat from conspecific alarm calls.

Call combination production is linked to the social environment in Western Australian magpies ( Gymnorhina tibicen dorsalis )

“…Vocally, magpies display high communicative flexibility, including a lifelong capacity for learning mimicry [55]. Their vocal system encompasses a range of vocalization types, including a discrete and combinatorial repertoire [21,56] and evidence for urgency coding in alarm calling [52,57]. In previous research, we quantified the magpie combinatorial repertoire (see figure 1 for examples of magpie call combinations), establishing the presence of non-random combining at both the within-and between-call levels.…”

“…Magpies are highly social birds that live in stable groups ranging from 2 to 11 individuals and that defend a territory year-round. Group members of all ages and sex interact frequently in a diverse range of contexts [48], such as provisioning young [49,50], antipredator behaviour [51,52] and social bonding through play [53,54]. Vocally, magpies display high communicative flexibility, including a lifelong capacity for learning mimicry [55].…”