COLONY-SITE AND NEST-SITE USE BY COMMON GRACKLES IN NORTH-DAKOTA

We searched 638 quarter sections (0.8 x 0.8 km) For Common Crackle (Qu iscalus quiscula) nesting sites in Benson County, North Dakota, in 198 9 and 1990. We found 3596 active nests in 202 colonies on 177 quarter sections. Colonies in shelterbelts next to inhabited farmsteads were f ound at greater than expected frequencies (P less than or equal to 0.0 5), whereas colonies in vegetation associated with potholes and miscel laneous habitats (woods, ravines. railroad easements, and lakesides) o ccurred below expected frequencies. Nest sites in stands of vegetation >100 m from farmstead residences occurred less frequently than expect ed (P less than or equal to 0.05). Within colonies, nest sites in blue spruce (Picea pungens), Siberian elm (Ulmus pumila) and black poplar (Populus nigra) were found at greater than expected frequencies (P les s than or equal to 0.05) according to these species' availabilities, w hile green ash (Fraxinus pennsylvanica). American elm (Ulmus americana ), and Russian olive (Elaeagnus angustifolia) were used below expected frequencies. The Common Crackle's preference for shelterbelts near in habited farmsteads affected the physical and vegetative characteristic s of colony sites and nest sites; with the exception of hawthorn (Crat aegus rotundifolia), colonized stands had species compositions typical ly found in multi-rowed farmstead shelterbelts in North Dakota.