Northern Prairie Wildlife Research Center
A secondary objective of the CRP was to enhance habitat for fish and wildlife populations. Grassland habitats established by the CRP benefit a variety of wildlife species (King 1991, Luttschwager and Higgins 1992, Hall and Willig 1994), especially breeding birds (Johnson and Schwartz 1993a,b; Kantrud 1993). Populations of many grassland birds have declined in recent decades, especially in areas of intensive agriculture, such as the Midwest (Warner 1994) and the northern Great Plains (Johnson and Schwartz 1993b). Johnson and Schwartz (1993b) found that the two most common breeding-bird species observed in CRP fields in the northern Great Plains were Lark Bunting (scientific names are in Table 1) and Grasshopper Sparrow, species that showed declines in midcontinental Breeding Bird Surveys by about 60% during the previous quarter-century. Other declining grassland species such as Dickcissel, Clay-colored Sparrow, Baird's Sparrow, and Bobolink were also common in many CRP fields (Johnson and Schwartz 1993b).
The objective of this paper is to estimate the relative importance of the CRP to breeding populations of grassland birds in North Dakota. We determined the changes in bird populations expected if the land enrolled in CRP were returned to crop production. We used available data collected in 1992 and 1993 from two independent studies in North Dakota: 1) surveys of statewide breeding-bird populations and 2) surveys of breeding birds in CRP fields.