Alarm calls of house wrens (Troglodytes aedon bonariae) elicit responses of conspecific and heterospecific species

Abstract

Nesting house wrens (Troglodytes aedon bonariae) use two basic alarm calls (Type I and Type II) when detect a threat near the nest. We experimentally analysed if calls distract predators or serve to recruit other birds to create a mobbing flock to deter predators. The results show that individuals preferentially position themselves in front of the threat, disclosing the location of the nest. Also, using playbacks of house wren alarm calls we found that these calls recruited both conspecific and heterospecific individuals to create a mobbing response. The alarm calls of house wrens seem to fulfil multiple functions, not only conveying information about the threat to their mates and nestling as revealed in previous studies, but also as a signal that attracts the attention of other conspecific and heterospecific individuals and can trigger a mobbing response to deter the predator.