Brown-headed Cowbird, <em>Molothrus ater</em>, Parasitism and Abundance in the Northern Great Plains

Conventional oil and natural gas infrastructure increases brown-headed cowbird (Molothrus ater) relative abundance and parasitism in mixed-grass prairie

The rapid expansion of oil and natural gas development across the Northern Great Plains has contributed to habitat fragmentation, which may facilitate brood parasitism of ground-nesting grassland songbird nests by brown-headed cowbirds (Molothrus ater), an obligate brood parasite, through the introduction of perches and anthropogenic edges. We tested this hypothesis by measuring brown-headed co...

Frequent Vocalizing Is Negatively Associated with Brood Parasitism in a Host of the Brown-headed Cowbird

Brood parasitism by the Brown-headed Cowbird (Molothrus ater) can substantially affect host species’ reproductive success. The “host-activity” hypothesis suggests that parasites eavesdrop on conspicuous behaviors to locate and parasitize hosts, and several studies of cowbird hosts support this hypothesis. In contrast, a recent study of the Least Bell’s Vireo (Vireo bellii pusillus) reported a n...

Brown-headed Cowbird (molothrus Ater) Parasitism on Warbling Vireos (vireo Gilvus) in Southwest Colorado Catherine

A8s~~nc~.-From May through July, 1993-1998 and 2001, effects of Brown-headed Cowbird (Molothrus ater) parasitism on 36 Warbling Vireo (Vireo gilvus) nests were documented in southwest Colorado. Overall parasitism was 75.0% and was the major source of nest failure. Among vireo nests that were not depredated, a significantly lower proportion of parasitized nests (10.2%) than nonparasitized nests ...

Nest desertion by blue-gray gnatcatchers in association with brown-headed cowbird parasitism

The blue-gray gnatcatcher, Polioptila caerulea, is one of the smallest regular hosts of the brown-headed cowbird, Molothrus ater. Gnatcatchers typically raise none of their own young when parasitized, yet anti-parasite behaviours have not been reported. A blue-gray gnatcatcher population in which pairs often desert nests when parasitized by cowbirds was studied to examine the success of a deser...

Brown-Headed Cowbird Parasitism of Lazuli Buntings; Relationships with Habitats and Ungulate Hosts