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

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.