Refuge in North Dakota. Prespray censusing 

 of sharp-tailed grouse, deer, and waterfowl 

 was accomplished, and prespray samples 

 were taken of soil, vegetation, aquatic in- 

 vertebrates, suspended matter in pond 

 water, and tissues from game animals for 

 chemical analysis and comparison with 

 postspray samples. 



Experimental testing of Compound 1080 

 baits for use in harvester ant control in 

 New Mexico was evaluated from the stand- 

 point of wildlife hazards. The preliminary 

 results indicated that the bait used was at- 

 tractive to wildlife and that some of the few 

 birds and rodents present in the sparsely 

 vegetated test area consumed lethal amounts 

 of the poison. 



Of considerable interest was the finding 

 of up to 0.9 p. p.m. of DDT and its metab- 

 olites in the tissues of 4 ducklings collected 

 near Yellowknife, Northwest Territories, 

 Canada, more than 500 miles fronn any 

 known pesticide-treated area. Tissues from 

 13 adult ducks collected in the Yellowknife 

 area contained an average of 0.3 p. p.m. 

 of DDT and metabolites, and 24 eggs an 

 average of 2.2 p. p.m. It is therefore postu- 

 lated that the adults picked up the pesti- 

 cides on their wintering grounds and passed 

 them along to their ducklings through the 

 eggs. 



The effect of sublethal amounts of endrin 

 on a small mammal population when applied 

 under field conditions is being studied by 

 the Ohio Unit. An application of 0.6 pounds 

 per acre of endrin had no apparent effect 

 on populations of meadow voles. Satisfactory 

 bioassay techniques have been developed 

 for determining minute quantities of endrin 

 in meadow vole tissue. Mascerated voles 

 are steam-distilled, and the resultant dis- 

 tillate is assayed in tanks of live guppies 

 held at constant temperatures. 



Ohio Unit researchers also are attempt- 

 ing to develop a method of ascertaining the 

 eventual dispersal of an insecticide in an 

 ecosystem by using an insecticide marked 

 with a radioactive isotope (S-^^). Quantities 

 of S-^^ were detected in insects, minnows, 

 worms, mice, and turtles taken from plots 

 sprayed with labeled malathion. Dusky- 



winged fungus gnats showed the highest 

 quantity of radioactivity in comparison with 

 other insect groups. More basic studies of 

 this general nature are needed in order 

 to assess the effects of pesticides on the 

 ecologic complex. 



Wildlife diseases and parasites 



The problem whether birds are import- 

 ant in transmission of encephalitis to man 

 and horses was investigated in a series of 

 field surveys. A temporary field labora- 

 tory was set up in the Chincoteague- 

 Assateague area of the Atlantic coast under 

 the auspices of the Patuxent Wildlife Re- 

 search Center, the Walter Reed Army 

 Institute of Research, and the University of 

 Maryland. The area was especially suitable 

 for study because of its isolation and the 

 presence both of wild ponies and of large 

 numbers of birds. The presence of eastern 

 encephalitis virus had been demonstrated 

 previously. Blood samples were taken from 

 approximately 1,500 birds. Mosquitoes also 

 were collected and processed for virus 

 isolation. Antibodies were demonstrated in 

 18 birds, including 5 clapper rails, 2 snowy 

 egrets, 2 brown thrashers, 5 catbirds, 2 

 yellow-breasted chats, 1 towhee, and 1 

 robin. 



A species of Plasmodium, the organism 

 involved in mosquito-borne malaria, was 

 isolated from a Canada goose at the Seney 

 National Wildlife Refuge by blood inocula- 

 tion into a 3-week-old domestic goose. 

 Although blood smears have shown Plas- 

 modium infection in geese, this was the 

 first isolation of a natural infection. Tests 

 of the isolate have shown that mallard 

 ducks are susceptible and that chickens 

 cannot be infected. 



A strain of T r ypano soma cruzi, the caus- 

 ative agent of Chagas disease in humans in 

 Central and South America, has been found 

 in about 2 percent of the raccoons trapped 

 at the Patuxent Center. This represents the 

 most northern known occurrence of this 

 parasite. Experimental study of isolates 

 showed that the raccoon strain was much 

 less virulent than the one occurring in 

 man. Other species of animals besides 



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