Domestic chicken hens can eavesdrop on the alarm calls of wild tits

Abstract

Eavesdropping on heterospecific alarm calls is common in nature, and successful eavesdropping on heterospecific call information can provide benefits to animal survival. Previous studies have shown that free-ranging flocks of domestic chickens can respond to avian heterospecific alarm calls. However, there are limited studies on whether solitary active domestic chickens (Gallus gallus domesticus), especially hens with chicks eavesdrop on heterospecific alarm calls to detect different types of predators and adjust their response depending on whether the predators are a threat to themselves or their young. In the present study, we evaluated the behavioral responses of hens with chick activity to two alarm calls (test playback) and territorial calls (control playback) of wild Japanese tits (Parus minor). The results showed that hens were more vigilant toward the alarm calls than territorial calls and that anti-predator behavior differed significantly between the two alarm calls as predicted: they engage in self-preservation behaviors when the call informs about aerial predators, and in protective behaviors of their chicks when the calls inform about ground predators. In the later case, the number of chicks also has an impact on the behavior of hens (dilution effect). This suggests that hens can eavesdrop on the alarm call of Japanese tits, identify predator information in the alarm call, and adjust the anti-predation strategy based on the type of alarm and the number of chicks.