Reducing impacts of brood parasitism by Brown-headed Cowbirds on riparian-nesting migratory songbirds

摘要: Riparian habitats throughout the Southwest have been altered directly and indirectly by human activities. Many migrant songbird species specific to riparian communities during breeding season are experiencing population declines. Conversely, Brown-headed Cowbird (Molothrus ater) benefits from fragmentation of, livestock grazing in near habitat. Brood parasitism cowbirds may accelerate process of local extirpation small, remnant populations migratory songbirds. trapping programs successfully reduced brood Least Bell’s Vireo (Vireo bellii pusillus) Southwestern Willow Flycatcher (Empidonax traillii extimus) California. This removal technique has not used commonly other states but be beneficial if a significant problem is identified. Preliminary surveys should conducted determine abundance distribution cowbirds, nests potential hosts monitored assess rate parasitism. It likely that songbirds can sustain rates greater than 30%. We provide trapping, habitat restoration. research suggestions improve management strategies for cowbird host nesting zones.