Dickcissel Relative Abundance Map
Source: North American Breeding Bird Survey (BBS)
Map Description:
The Dickcissel is an enigmatic grassland bird, whose status and distribution have always been confounded by its pattern of irregular movements. This species is believed to have originally occupied the tall grass and mixed prairies of the eastern and central Great Plains. Historical changes in its breeding range have been associated with large-scale changes in agricultural land use practices (Hurley and Franks 1976). Deforestation allowed this species to spread eastward during the nineteenth century (Peterjohn and Rice 1991). Additionally, Dickcissels were well established summer residents along the Atlantic coastal plain during that century. This population largely disappeared late in the nineteenth century (Gross 1921), so little is known about its origins, status, and distribution.

Sauer, J. R., B. G. Peterjohn, S. Schwartz, and J. E. Hines. 1995. The Grassland Bird Home Page. Version 95.0. Patuxent Wildlife Research Center, Laurel, MD

Cautions for this Product:
Analysis and interpretation of BBS data is tricky, because the survey incorporates information from a huge geographic area and the survey varies greatly in quality of information over the area. To document some of the problems with the analyses of BBS data, and help interpret the results presented, a series of help files is provided with information on the survey, discussion of problems with analysis, and details on how the presented information should be interpreted.
For Further Information: