Date of this Version
Since 1979, the Denver Wildlife Research Center, U.S. Fish and Wildlife Service, has conducted an accelerated research program on the blackbird-sunflower problem which occurs annually in the Dakotas and Minnesota. The objective is to develop effective, cost beneficial and environmentally safe methods for reducing blackbird damage to ripening sunflower. A multidisciplinary approach involving interrelated studies of problem definition, ecology, and control methods development is being used. Preliminary results are presented from several studies involving: state- and county-wide estimates of damage; frequency distribution and timing of damage; compensatory growth in early damaged sunflower heads; breeding male blackbird censuses; mass-marking migratory red-winged blackbirds (Agelaius phoeniceus) in spring roosts; food habits of red-wings; the chemical frightening agent, 4-aminopyridine; the avian repellent, methiocarb; decoy crops for blackbirds; frightening devices; and bird-resistant varieties of sunflower. Management strategies suggested from these studies are provided.