Despite the fact that 97% of cowbird eggs and nestlings do not survive to adulthood, brood parasitism
by cowbirds has pushed birds of some host species to the status of "endangered" and has probably hurt populations of birds of some other host species.
Rather, nesting success appeared to be governed by local effects of brood parasitism
and predation, which can thus lead to ecological and perceptual traps in the region.
Interspecific brood parasitism
, a form of social parasitism, is a behavior in which the female of one species deposits her eggs in the nest of another species.
An example of a benefit of brood parasitism
is "exceedingly unusual and cool," says Claire Spottiswoode, an evolutionary biologist at the University of Cambridge.
With a decline in the amount of suitable habitat paired with brood parasitism
by the brown-headed cowbird (Molothrus ater), the Kirthland's warbler population fell to a mere 201 pairs in 1971.
They transplanted pickerelweed plants in the Cache River Wetland, built and posted nesting boxes to research brood parasitism
in bird species, created more than 200 educational binders for local teachers, made and donated children's books to the community's Wetland Center, presented research at a science symposium, created a website and more.
Although rates of brood parasitism
by brown-headed cowbirds (Molothrus ater) are high in some warbler species (Ortega, 1998), there are relatively few published accounts with yellow-throated warblers as the host.
The cuckoo is the only British bird that practises brood parasitism
- this is when they lay their eggs in another bird's nest and use them as foster parents.
by Brown-headed Cowbirds, WNV infection, loss of wintering habitat of neotropical migrants, and habitat degradation and loss on breeding ranges are all factors acting on populations of North American birds (Terborgh 1989, Causey and others 2003).
As a result, birds that were attracted to playback sites in this area had low brood parasitism
rates and high nesting success (Ward & Schlossberg 2004).
Hosts employ many strategies to prevent brood parasitism
Each account includes a range map; a capsule statement identifying key components for managing habitat for the species; a table of habitat requirements organized by author and state or province; sections on suitable habitat, area requirements, brood parasitism
, breeding-season phenology, species' response to management, and management recommendations; and literature cited.