EXTENDED USE OF STARLICIDE IN REDUCING BIRD DAMAGE IN SOUTHEASTERN FEEDLOTS

The livestock industry is a major agricultural activity in the Southeast where large numbers of wintering blackbirds and starlings (Sturnus vulgaris) consume and con- taminate feed at livestock feeding operations. This study was conducted in Tennessee, where the 1977 cash sales for cattle, hog, and dairy products approximated $579 milion or 42% of sales of all Tennessee farm commodities (Tennessee Crop Reporting Ser- vices 1978). Although no feeding operation damage figures are available, losses to birds at feedlots may be as great or greater than depredations to wheat and corn crops (Stickley et al. 1976, Dolbeer et al. 1978, Dolbeer et al. 1978-79, and Stickley et al. 1979). Besser et al. (1968) calculated the average daily time starlings fed at Colorado feeding operations, and, on the basis of feed consumption by caged birds, estimated that one starling would consume 28.3 g of livestock feed per day. Farmer questionnaire data (Russell 1975) indicated substantial feeding operation losses, but these data were not differentiated into disease versus feed losses or losses by bird species. DeCino et al. (1966) showed that 3-chloro-4-methyl benzamine HCI (the active ingre- dient in Starlicide) was highly toxic to starlings (acute oral LD50 of 3.8 mg/kg), well ac- cepted by the species, generally less toxic to other avian forms, and relatively nontoxic to mammals. They found hawks to be particularly resistant to the chemical, and in- dicated that hazards to hawks from eating Starlicide-affected birds would be low. The compound causes a slow, nonviolent death primarily through uremic poisoning and con- gestion of major organs. Most birds ingesting the chemical die within 8-48 h. The for- mulated product is now registered under the trade name “Starlicide CompleteR” by Ralston Purina Company, St. Louis, Missouri. It consists of 160-180 mg protein-based pellets of which one in 10 contains 1 % of the avicide. Besser et al. (1967) were the first to test this chemical operationally by ground-baiting a two-acre Nevada cattle feeding operation with 10 Ib of 1% Starlicide-treated poultry pellets that reduced a population of 2280 starlings approximately 75 percent within seven days. No secondary hazards were noted. In a similar study Royall et al. (1967) reduced a population of 1800 starlings at a Utah turkey farm by about 93% after four days. West (1968) conducted the only published long-term study of the effectiveness of baiting with Starlicide at a feeding operation. Preroosting birds using a Colorado feedlot were baited in the afternoon 19 times from 23 November to 3 March with pellets broad- cast on the ground once. During this period, the initial 250,000 starling population was reduced 80% by 29 January. The above studies were conducted at western feedlot operations, and, with the ex- ception of the West (1968) study, were of short duration. Further, effectiveness of these studies was determined by the estimated reduction of starling populations at the feeding operations based on area population estimates and bait consumed. This pre- sent study was designed to determine the effectiveness of extended baiting under eastern livestock feeding conditions by evaluating activity of starlings/blackbirds at specific feed troughs or feeding areas. Eastern livestock operations tend to be smaller scale than western operations and more variable in terms of operating conditions