Brown-headed Cowbird (Malodorous ater)

Brown-headed Cowbird
Malodorous ater

The Brown-headed Cowbird (Molothrus ater) is widespread across most of North America. It feeds on seeds as well as insects which are stirred up by grazing cattle, thus the common name of cowbird. This species is a nest parasite which means the female lays her eggs in the nests of other birds and thus the cowbird does not raise its own young. This was an excellent strategy hundreds of years ago when this species was known to follow the American Bison during that animal's migration. By laying its eggs in other birds' nest the cowbird could remain with the bison heards and not have to stay behind to raise young. In modern times, however, man has cleared more and more land thus creating grazing lands for cattle where there used to be forest. Cowbirds have increased their numbers to the extent that they are a true threat to many native American species. At times it seems as if certain warblers and vireos are only raising young cowbirds instead of their own offspring. The next two shots at right of a female Brown-headed Cowbird are digital captures in May, 2006, with a Canon EOS 1D Mark II and EF 500mm F/4 L IS lens and 1.4X extender in Hidalgo Co., Texas. Brown-headed Cowbird Molothrus ater female Las Colmenas Ranch near McCook, Hidalgo Co., Texas 16 May 2006
Brown-headed Cowbird Molothrus ater female Las Colmenas Ranch near McCook, Hidalgo Co., Texas 22 May 2006
The image at right of another female was shot in Kenedy Co., Texas in April, 2002, with a Canon EOS 1V and EF 500mm F/4 L IS lens on Fuji Velvia.
Brown-headed Cowbird Molothrus ater male Lipscomb, Lipscomb Co., Texas 15 April 2007
Brown-headed Cowbird Molothrus ater female Bear River N.W.R., Box Elder Co., Utah 12 June 2007
Brown-headed Cowbird Molothrus ater female Bear River N.W.R., Box Elder Co., Utah 12 June 2007
The female Brown-headed Cowbird shown here was in Austin, Travis Co., Texas, in April, 2008. This shot was taken with the same gear as the two shots just above.
The male in the next two shots was at Big Bend National Park, Brewster Co., Texas, in May, 2010. These shots were taken with with a Canon EOS 1D Mark IV and an EF 800mm F/5.6 L IS lens.

The next four shots of Brown-headed Cowbird (two images of a male and two images of a female) were taken near Laredo, Webb Co., Texas, in February, 2011.