Cooperative Functions of Duetting Behaviour in Tropical Wrens
Vocal duets occur when two breeding partners coordinate their songs into a joint display. Duetting serves functions both within and between pairs, and functionality is often context dependent. I explore the function of temporal coordination of male and female songs into duets, testing the hypothesis that coordinated duets are more threatening territorial signals than poorly coordinated duets or solos in three closely related species of wren. Results indicate that birds respond with similar levels of physical aggression to all three levels of coordination; however, they sing more duets in response to both categories of duets. I also explore duets and other vocalizations as they are used during breeding, testing the hypothesis that duets play a role in coordinating nest visitation. Contrary to my predictions, the birds sang the most duets during the incubation stage. My results suggest that duets are used for both territory defence and communication at the nest.