Date of this Version
To successfully reduce blackbird (Icteridae) damage to sunflower crops in the northern Great Plains, wildlife damage managers must be able to identify sites where large roosts could form in spring and fall. In 1998 and 1999, we measured several habitat and land-use characteristics of spring and fall blackbird roosts. Our objective was to quantify the relationship between roost formation and wetland habitat and land-use. We used data from 7 spring roosts and 12 fall blackbird roosts to set search guidelines that might increase the efficacy of locating potential roost sites in the Prairie Pothole Region of the northern Great Plains. Analysis of land use with aerial photography and on-site measurements of wetlands showed that roosts were usually established in larger-sized wetlands with sufficient standing water to produce large robust stands of cattail (Typha spp.). Large roosts often formed near harvested cornfields in spring and near ripening sunflower in fall.