REFORMULATED 4-AMINOPYRIDINE BAITS COST-EFFECTIVELY REDUCE BLACKBIRD DAMAGE TO RIPENING CORNFIELDS

In 1984 4-aminopyridine baits, stabilized with hydrochloric acid, were appraised in ripening cornfields being attacked by blackbirds on the Sand Lake National Wildlife Refuge., South Dakota. In 1982, i t had been discovered that 4-aminopyridine, the active agent in commercial Avitrol® baits for crop protection rapidly vaporized at summer storage and field baiting temperatures. In July, baiting lanes were created in 12 cornfields by destroying every 55th row. In August after a 3-day pretreatment period, fields were baited with Avitrol® FC Corn Chops-99 for a 2-week period when corn was most vulnerable to damage. Bait was applied from baiting lanes at the rate of 1 Ib/acre of field with an electric seeder mounted on an all-terrain cycle. Rebaitings were made at half the initial rate; 0 to 3 rebaitings were needed, largely because of depletion of baits by insects and rodents. An insecticidal pretreatment, 5% carbaryl pellets, did not significantly lower the rate of bait depletion. Blackbird damage was 87% less (P=\u3c0.001) during the baited than the pretreatment period (19 vs 142 bu of corn lost per day). From 2,000 to 17,000 blackbirds, mostly red-winged and yellow-headed blackbirds, were observed in test fields. An estimated 825 dead or affected blackbirds and 1 mourning dove were observed or collected in test fields. Application of baits on baiting lanes with a seeder mounted on a cycle proved both economical and efficient . About 100 acres/h were baited at an estimated cost of \u3c15 cents/acre/application. About $5:50 worth of corn was saved for each$1 spent for bait and loss of corn yield in baiting lanes. Growers would have saved about $400/h for time spent in creating lanes and baiting

STARLING CONTROL IN LIVESTOCK FEEDING AREAS

The Denver Wildlife Research Center has been investigating methods to combat starling (Sturnus vulgaris) problems at livestock feeding areas since 1960. A variety of chemicals, baits, and methods of bait placement have been tested. This paper summarizes these investigations. CHEMICALS TESTED About 500 chemicals have been screened for toxic and stupefacient effects on starlings. Although several chemicals have been found that immobilize starlings in the laboratory, they have been largely ineffective in the field; most starlings regurgitate the treated baits, and seldom have substantial numbers been affected. Of the toxicants screened, four compounds, TEPP, DRC-632, DRC-1327, and DRC-1339, have shown enough activity as control agents for starlings to warrant intensive investigation in the laboratory and the field

DRC-1339 IN FEEDLOTS

Since 1960, the Denver Wildlife Research Center has been investigating methods of controlling starlings (Sturnus vulgaris) at livestock feedlots. One chemical developed at the Denver Center is a slow-acting avicide, DRC-1339 (3-chloro-p-toluidine); it is well accepted and highly toxic to starlings, generally less toxic to other birds, and relatively nontoxic to mammals. It possesses no secondary hazard to avian and mammalian predators. A Cooper\u27s hawk (Accipiter cooperii), a marsh hawk (Circus cyaneus), and a sparrow hawk (Falco sparverius) subsisted on field-killed DRC-1339 starlings for 3- and 4-month periods with no ill effects. In our tests, poultry pellets (Purina Layena Checkers\u27) have been the most effective and selective starling bait. Field tests in many states have shown the utility of this compound when applied to pellets. Pellets were treated to contain approximately 1 percent DRC-1339, diluted with untreated pellets and grains, and broadcast in pens and alleys at cattle feedlots and on the perimeters of pens at turkey feedlots. Baiting rates varied from 2 to 10 lbs. of treated pellets per acre, depending on the size of the lots; dilution rates were generally 1:10. DRC-1339 has proved to be an extremely effective and safe toxicant for starlings at animal feedlots. It is now marketed commercially under the trade name of Starlicide

NEW MATERIALS FOR BIRD CONTROL

A variety of methods is necessary to solve the many bird damage problems that occur in agriculture and other fields of interest. It is apparent that no one method can be used to provide answers for all damage situations; each problem and problem area is unique and requires thorough knowledge and investigation before intelligent measures of bird control can be applied. Thus, basic research in the laboratory and initial field studies are necessary to arrive at the most safe, efficient, and economical method of bird damage control possible for each situa-tion. The use of chemicals for damage control is one of the major approaches in solving bird damage problems, and personnel of the Denver Wildlife Research Center rely heavily on this line of attack. The following is a resume of the various chemical agents that (1) are in the initial phases of investigation and show promise, and (2) are nearing the final stages of research and hopefully will become operational. I think the pendulum is still swinging and swinging towards conservative view of uses that we may want to make of any pesticide. Some recent rumblings from Washington raising questions about new limitations on products that we\u27ve been using for ten years or more seem to support this concern. I think these problems underline the mention that\u27s just been made by Dan about the necessity of having a great deal of data, and data which is much more specific and comprehensive than we have realized in the past. If we\u27re going to have these products, either we\u27re going to have to lean entirely on government agencies to develop these things or else cooperate with private industry. Together we must work out the answers

World bird damage problems

There is a lack of information on bird-caused economic losses on a worldwide basis. Some estimates are available for specific problems in the United States, Canada, and parts of Oceania and Europe, but loss estimates are almost totally lacking in Latin America, Asia, and Africa. To justify development of control programs, it is desirable that reliable data on losses be obtained. Such data are helpful at all levels of decision-making about bird control, from research to implementation. Bird damage situations throughout the world are similar, involving many of the same crops and genera of birds. This report summarizes major damage problems reported for each continent in tabular form. Agricultural problems are emphasized; other examples are given including bird hazard to aircraft, predation by undesirable species, urban and rural roost problems, birds as carriers or transmitters of disease, and beneficial aspects of some species. Control methods are not reviewed

Methods of controlling blackbird damage to field corn in South Dakota

Recent research efforts to control blackbird damage to corn in South Dakota are described. The primary species responsible is the red-winged blackbird, but other associated species include yellow-headed and Brewers blackbirds, common grackles, and brown-headed cowbirds. The birds’ biology and behavior are described, as is damage assessment in corn fields. Bird banding efforts have revealed typical bird migration patterns and movement. Trapping with Miller-type cannon nets and with modified Australian crow traps have shown success. Other damage control techniques considered, investigated, and/or evaluated include bird-resistant variety of crops, habitat management, use of frightening devices, roost sprays with the organophosphate DRC-632, and baiting with the fright-producing chemical DRC-1327

BIRD DAMAGE TO PEANUTS AND METHODS FOR ALLEVIATING THE PROBLEM

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