Function of pair duets in the eastern whipbird: Cooperative defense or sexual conflict?

Abstract

Paired male and female eastern whipbirds, Psophodes olivaceus, sing precisely coordinated, male-led duets. Four broad explanations have been proposed for the function of duets: 1) cooperative resource defense, 2) prevention of partner usurpation, 3) defense of an individual's own position within the partnership, or 4) mate identification and localization. These 4 hypotheses make different predictions about how male and female residents should respond to simulated intrusion by other pairs or individuals. We compared the behavioral and vocal responses of 20 pairs of eastern whipbirds to simulated territorial intrusions by: 1) a solitary singing male, 2) a solitary singing female, and 3) a duet..