AGRICULTURAL IMPACT OF A WINTER POPULATION OF BLACKBIRDS AND STARLINGS

The major concentration of blackbirds and Starlings (Sturnus vulgaris) in North America occurs in the southeastern United States where an estimated 350 million Red-winged Blackbirds (Agelaius phoeniceus) , Common Grackles (Quiscalus quiscula) , Brown-headed Cowbirds (Molothrus ater) , and Starlings congregate in winter roosts (Meanley 1971, 1975, 1977). An estimated 75-100 major (containing \u3el million birds) roosts form in the southeastern states each year. Increasing attention is being given to many of these roosts because of nuisance problems, reputed health hazards, and agricultural damage associated with them. Although considerable effort has been directed toward developing methods for reducing roosting populations (Lefebvre and Seubert 1970), field applications of such methods have met with considerable public opposition (Graham 1976). Unfortunately, little effort has been directed to ecological studies of the various roosting species during the winter months. The objectives of this study were: (1) to document food habits, habitat preferences and use, and general feeding and roosting behavior of the various blackbird species and Starlings using a large winter roost; and (2) to undertake a preliminary survey of the impact that this large roosting population has on agriculture within a 40 km foraging radius of the roost