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Research efforts to combat the problem of European starling damage in livestock feeding areas (feedlots) by developing appropriate toxicants and stupefacients are described. Of about 500 chemicals screened for possible utility, 4 compounds showed promise at potential toxicants for further development and testing: TEPP (tetraethyl pyrophosphate), DRC-632 (0-[4-(methylthio-m-tolyl] phosphorothioate)), DRC-1327 (4-aminopyridine), and DRC-1339 (3-chloro-p-toluidine hydrochloride). TEPP was found to be too toxic to mammals to further develop its potential use against starlings. However, because it causes rapid death, it was useful in subsequent tests of bait acceptance by various avian species. DRC-632 was the first material noted to be far more toxic to birds than to mammals. Dermal toxicity proved more important than oral toxicity, but its extreme secondary hazard, especially to avian predators and scavengers, made it generally unsuitable for use. DRC-1327 was found to cause birds to emit distress cries and violent reactions in birds ingesting the materials, which often died, but also causing flocks to abandon the treated area. Field trials showed promise, and when bait acceptance by starlings is poor or fair, it is more effective than other known toxicants in reducing damage. DRCC-1339 (Starlicide) is the most selective bird toxicant presently known, providing starling control that is virtually nonhazardous to other animals. Discussions of bait materials and formulation, active ingredient dilutions, and baiting methods are provided.

Investigations from 1969 through 1971 of bird damage to peanuts in south-central Oklahoma have shown that losses are caused mainly by common grackles (Quiscalus quiscula). These losses, as high as $36 per acre, have been reduced primarily through the use of exploders and early harvesting of the crop. A fright-producing chemical, 4-aminopyridine, was also effective in scaring grackles from windrowed peanut fields. Banding has shown that many of these grackles breed in western Nebraska and Kansas and winter in northeastern Texas.

In 1968 and 1969, biologists of the Denver Wildlife Research Center made field surveys in six Latin American countries to obtain information on bird damage problems in agriculture, under an agreement with the Agency for International Development. Species of icterids, fringillids, psittids, columbids, and anatids caused most of the damage. Grain sorghum, corn, and rice were damaged most heavily. Other crops such as soybeans, wheat, cacao, and mangoes were also damaged, but seldom seriously. Resident post-breeding populations of birds in Latin America cause some damage to crops in summer, the tropical wet season; however, migrants from the United States and Canada greatly swell these problem populations in winter, the tropical dry season, when smaller acreages of mostly irrigated crops are available. Problems also intensify in October when the largest numbers of migrants descend upon ripening crops and, again, in April when many crops are being planted. Bird damage problems in Latin America are similar to those in the United States, involving many of the same types of crops and genera of birds. Therefore, research conducted in one area should be beneficial for the other, and cooperative work is recommended.

Red-winged blackbirds (Agelaius phoeniceus) have been discouraged from using cattle feedlots near Denver, Colorado, by baiting alleys with cracked corn treated with an aversion-producing immobilizing agent, DRC-736 [4-(methylthio)-3,S-xylyl N-methylcarbamate]. In three studies, large populations of redwings were reduced 70% - 98% within a few days and protection lasted about a month. In a fourth study, simultaneous baiting of three heavily used feedlots reduced redwing use by more than 90% within hours and was apparently responsible for these birds abandoning their roost and relocating in areas where they caused little trouble. Mortality was low (less than 5% of affected redwings in the fourth study), and few birds of nontarget species were affected.