Comparative reproductive ecology of co-occurring rare and common vireos in shrublands and woodlands

Abstract

ABSTRACT Black-capped Vireos (Vireo atricapilla) and White-eyed Vireos (Vireo griseus) are closely related and ecologically similar. Despite these similarities, the White-eyed Vireo is widely distributed and common, whereas the Black-capped Vireo has a restricted breeding range and is currently federally endangered in the United States and Mexico. Here we address this apparent paradox with a comparative ecological study of co-occurring Black-capped and White-eyed vireos. We studied vireos in shrublands and woodlands in central Texas, USA, in 2013 and 2014. We used point count surveys (n = 256) and nest monitoring (n = 144) to determine arrival dates, settlement patterns, nest site selection, and nest survival relative to temporal and habitat factors. Additionally, we conducted reciprocal playback trials (n = 16) to test for the presence of interspecific aggression. White-eyed Vireos arrived first and established territories in both habitats with equal probability. Black-capped Vireos arrived after White-e...