High Rates of Nest Usurpation by Grayish Baywings ( gelaioides badius) in Active Nests of House Wrens (Troglodytes aedon) in Central Andes

Abstract

Nest usurpation is a behavior where one individual takes over the active nest of another individual of the same or a different species. The Grayish Baywing (Agelaioides badius) has been reported as an occasional inter-specific nest usurper. House Wrens (Troglodytes aedon) nests usurpation by Grayish Baywing has been reported as an anecdotal observation in previous studies. In this paper we report that nest usurpation by Grayish Baywing is the second cause of breeding failure in a House Wren population in the Central Andes.