Habitat Characteristics of Spring Blackbird Roosts in East-central South Dakota

Authors

H. Jeffrey Homan, United States National Wildlife Research Center, Great Plains Field Station, Bismarck, North DakotaFollow
Richard S. Sawin, North Dakota State University-Fargo
George M. Linz, United States National Wildlife Research Center, Great Plains Field Station, Bismarck, North DakotaFollow
William J. Bleier, North Dakota State UniversityFollow

Date of this Version

9-2006

Document Type

Article

Citation

The Prairie Naturalist (September 2006) 38(3): 183-193

Associate editor for ornithology: Gregory A. Smith

Comments

United States government work

Abstract

In the northern Great Plains, blackbirds (Icteridae) roost almost exclusively in emergent-dominated wetlands. The physical characteristics of wetland roosts are not well understood. From March 20 to April 20, 1999, we studied 16 wetlands used as blackbird roosts in east-central South Dakota. Six wetlands had major roosts (range: 102,000-298,000 blackbirds); whereas, 10 wetlands had minor roosts (range: 2,010-34,000 blackbirds). Maximum roost size was correlated directly with emergent vegetation area (P = 0.05) and possibly with wetland basin area (P ≤ 0.10). Water depths were greater at used sites within wetlands of major roosts (median = 44 cm) than at used sites of minor roosts (median = 25 cm). Palustrine wetlands with large expanses of emergents (> 100 ha) and water depths (> 40 cm) had an increased likelihood of developing into major spring roosts in east-central South Dakota.