Predation is the leading cause of avian nest failure, and parents should benefit from choosing nest locations that limit their predators’ ability to detect nests (i.e., nest concealment hypothesis). To understand how nest concealment and other nest-site vegetation characteristics affect the likelihood of predation by specific predators, we used camera traps to monitor predator activity at the nests of Black-throated Sparrows (Amphispiza bilineata) in desert scrub habitat in central New Mexico. After a nest fledged or failed, we measured the dimensions of the nest shrub, the average number of branches offering lateral concealment of the nest, and distance between the nest shrub and the nearest neighboring vegetation. We also used 50 m transects to survey plant community diversity in the vicinity of the nest shrub. Nest-site vegetation characteristics did not differ between nests that fledged and those that failed. In addition to confirming predator activity by Brown-headed Cowbirds (Molothrus ater) and coachwhips (Masticophis flagellum), which have been reported previously, ours is the first study to report that striped skunks (Mephitis mephitis) and gray foxes (Urocyon cinereoargenteus) also prey on Black-throated Sparrow nests. This study broadens our understanding of the predator guild for Black-throated Sparrows and other low-nesting birds but suggests that vegetative concealment has limited effects on nest fate in this species.

This content is only available as a PDF.
You do not currently have access to this content.