Wild great tits' alarm calls prompt vigilant behaviours in free-range chickens

Free-range domestic chickens can distinguish between different alarm calls of Japanese tits

Heterospecific eavesdropping of alarm information is an anti-predator adaptation in the wild as it improves the monitoring of shared predators and hence provides opportunities to avoid predators. Our current understanding of heterospecific eavesdropping information is based primarily on studies of bird, primate, or ungulate populations in the wild, whereas little is known regarding the ability of domesticated species to respond to alarm signals from wild individuals. Using sound playback experiments, we assessed the behavioral responses of free-range domestic chickens (Gallus gallus domesticus) in Hainan to alarm calls (test playback) and songs (control playback) of wild Japanese tits (Parus minor). The results revealed that free-range domestic chickens showed greater vigilance to the alarm calls of Japanese tits than to the songs of Japanese tits, especially their alarm calls for Siberian chipmunks (Tamias sibiricus). Furthermore, individual-foraging single chickens were significantly more vigilant than those foraging collectively in groups. Our findings suggest that free-range domestic chickens are as capable as wild birds in responding to heterospecific alarm calls and are likely to be able to distinguish between different types of heterospecific alarm calls.

Avian Alarm Calls Do Not Induce Anti-Predator Response in Three Anuran Species

Many species produce alarm calls in response to predators, and the anti-predator signals are often used by other species. Eavesdropping on heterospecific alarm calls has been widely found in bird and mammal species. Other taxa, such as reptiles and amphibians, however, receive limited attention at present. Here, we selected three types of alarm calls of Japanese Tits (Parus minor) that were evoked by the Siberian Chipmunk (Eutamias sibiricus), Eurasian Sparrow Hawk (Accipiter nisus), and model snake (Elaphe spp.), respectively, and then carried out playback experiments to test whether three frog species changed their behaviors in response to the three treatments of Japanese Tit calls while the tit's territory song was used as a control. The results showed that Little Torrent Frogs (Amolops torrentis), Ornamented Pygmy Frogs (Microhyla fissipes) and Spot-legged Treefrogs (Polypedates megacephalus) did not jump off their positions in response to the same four acoustic signals. They also did not change their calling behaviors in response to the alarm calls of Japanese Tits. This study found no evidence that these anuran species can eavesdrop on heterospecific tits' alarm signals.