Vertebrate Pest Conference Proceedings collection


Date of this Version

March 1984


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.