A Range-Wide Survey of the Endangered Black-Capped Vireo in Texas

Abstract

Vireo atricapilla (Black-capped Vireo) is an endangered migratory songbird with a breeding range that exists predominantly within Texas. Despite the species' listing under the Endangered Species Act in 1987, Black-capped Vireos were largely undocu- mented in much of the range. We sampled over 10,700 points in Texas, resulting in 2458 Black-capped Vireo detections. We examined the relationship between Black-capped Vireo occurrence and vegetation and broad-scale landscape variables, and we assessed if detections were clustered. Black-capped Vireo detections occurred often on a common soil type but were found where slopes were higher in the western part of the range. We found evidence of clustering in six of our eight study areas but no evidence of habitat metrics driving that clustering. These data improve the current knowledge of Black- capped Vireo distribution and offer opportunities for improved guidance for conservation and management efforts.