Anthropogenic noise reduces approach of Black-capped Chickadee (Poecile atricapillus) and Tufted Titmouse (Baeolophus bicolor} to Tufted Titmouse mobbing calls.

Successful communication between a sender and a receiver is critical for coordinating behaviors between organisms. This coordination can be disturbed by anthropogenic noise, which has been shown to alter vocal signal production in many species of birds. In addition to affecting senders, noise may also alter reception and behavioral response. Here we investigated the effects of anthropogenic noise on behavioral response to acoustic signals in mixed-species flocks of songbirds. We used playbacks of Tufted Titmouse (Baeolophus bicolor) chick-a-dee calls and local anthropogenic noise to determine how receivers respond to calls with and without added noise. We found that the addition of noise caused a significant decrease of ~80% in the number of birds that approached the speaker during a chick-a-dee call playback; however, we saw no effect of noise on feeding behavior. Our data support the hypothesis that anthropogenic noise can alter behavioral responses to chick-a-dee calls. This finding is of particular concern because chick-a-dee calls are given in response to a threatening stimulus. If receivers are slow to respond to these warnings, they may be unable to take advantage of the warning. [ABSTRACT FROM AUTHOR]