||The Conservation Reserve Program (CRP) has effected major changes to the landscape, especially in the northern Great Plains. Breeding birds have responded dramatically to habitat changes by colonizing CRP
fields, often in large numbers. The vegetation in most CRP fields consists of introduced grasses and legumes, along with a variety of weedy species. This paper describes the bird populations found during three years of surveys on more than 300 CRP fields in western Minnesota, North Dakota, South Dakota, and eastern Montana. We relate densities of selected species to geographic location, annual effects, conservation practice adopted, and vegetation features.