research in tlie East. Biologists assigned to the 

 Center and stationed at Gadsden, Ahi., are meas- 

 uring tlie effects of dieldrin and heptachlor on 

 wildlife in the Sovitheast, where these chemicals 

 are used in a large-scale program against the im- 

 ported lire ant. In thi-ee field tests they have 

 found that bobwhite fniail populations were re- 

 duced 85 pei-cent after applications of 2 pounds 

 of granular lieptachlor to the acre. In these same 

 tests, many other bird and mannnal species were 

 also sharply reduced in numbers. 



Several universities, under contracts with the 

 Bureau of Sport Fisheries and Wildlife, are work- 

 ing with Patuxent scientists to find answei-s to 

 specific questions about the effects of dieldrin, hep- 

 tachlor, and other insecticides on migratory birds. 

 Chemists at Patuxent determine the amount of 

 poison in samples of birds and mammals found 

 dead in areas that have been treated with pesticide 

 chemicals. They conduct controlled experiments 

 with pheasants, quail, and mallard ducks to meas- 

 ure the effects of various pesticides on production 

 of eggs, hatchability of eggs, crippling of chicks, 

 and survival of young. These experiments have 

 revealed, for example, that ])heasants, fed a diet 

 containing small amounts of dieldrin, laid eggs 

 that hatched poorly and produced a greater than 

 normal number of cripj)led chicks. Bird-produc- 

 tion facilities at Patuxent are adequate to supply 

 1,000 mallard ducks, 3,000 quail, and 1,500 pheas- 

 ant each year for research on the physiological and 

 toxic effects of pesticide chemicals. 



Widespread chemical treatments underway in 

 the Southeast may affect many migratory birds 

 that winter there. The woodcock is particularly 

 vulnerable, as its winter range is centered in 

 the southern Coastal Plain. The principal food 



of this species is eartliworms, whicli can con- 

 centrate as much as 10 parts per million of poLson 

 in their bodies. By feeding on contaminated 

 earthworms, the woodcock can be slowly poisoned. 

 Patuxent biologists and cliemists are studying 

 trends in numbers of woodcock, their breeding 

 success, and the extent of poison contamination 

 in woodcock populations. In this effort, thousands 

 of sportsmen of the northern and northeastern 

 States are helping by sending in woodcock wings. 

 Since young of the year differ from adults in 

 certain wing features, biologists can use wings to 

 measure success of the breeding season and thei'eby 

 learn each year whether the birds have reproduced 

 normally. 



When first used for mosquito control over 

 marshes, DDT proved to l)e a very effective 

 pesticide. Witliin a few years, though, some 

 mosquitoes began to develop resistance to the 

 chemical, and again the mosquito problem was 

 acute. As doses had to be increased or more 

 poisonous materials used to accomplish control, 

 reports of damage to fish and wildlife increased. 

 Patuxent biologists are working with entomolo- 

 gists on this common problem in an effort to de- 

 velop mosquito-control techniques that will not 

 harm waterfowl and other wildlife and tiiat may 

 actually improve conditions for them. The most 

 promising leads inchule water-level control, 

 management of vegetation, and introduction of 

 fish that eat mosquitoes. 



Through intensive research on the hazards of 

 chemicals to wildlife and on substitute methods 

 for combating mosquitoes, the Patuxent Center 

 is contributing substantially to the development 

 of safer and nioi-e specific jnetliods of pest-insect 

 control. 



Chemist extracting 

 pesticides from 

 animal tissue. 



14 



