degrade only to DDE and DDA, the latter 

 being readily excreted. 



With expanded pen and laboratory fa- 

 cilities at both the Denver and Patuxent 

 Centers and with improved techniques, it 

 is now possible to screen commonly used 

 pesticides for acute and chronic toxicity 

 levels at a more rapid rate and on a 

 greater variety of wildlife. Among the 

 techniques developed was a "clean-up" 

 method for treating biological samples 

 being analyzed for the pesticide Sevin. 



% f"* 



-^^* 



Mule deer fawns in enclosures at Denver Federal 

 Center are kept for pesticide studies. They are fed 

 kpown amounts of pesticides to determine toxicity 

 and retention of the material within body tissues. 



(Photos by Denver Wildlife Research Center.) 



Field and laboratory studies . --Chemical 

 analyses of birds and mammals found dead in 

 areas treated for control of Japanese bettles 

 or white -fringed beetles contained up to 

 50 p. p.m. of dieldrin in their tissues. Con- 

 centrations in many of the approximately 

 250 specimens equaled or exceeded those 

 found in quail or pheasants that died after 

 exposure to dieldrin or aldrin in pen 

 feeding tests. 



The 1961 counts of quail numbers in a 

 Georgia area treated for the control of 

 the imported Jire ant with 2 pounds per 

 acre of heptachlor in 1958 showed that 

 populations had increased to a level that 

 was very nearly normal. 



Y-shaped rotary blender used for mixing diets contain- 

 ing pesticide. 



(Photo by Denver Wildlife Research Center.) 



A field study of survival of birds and 

 small mammals in a forest area treated with 

 DDT was nnade in cooperation with the U.S. 

 Forest Service at its Coweeta Hydrologic 

 Laboratory in North Carolina. Comparisons 

 on two areas treated w^ith 1 pound of chemi- 

 cal per acre and on two vmtreated areas 

 showed no significant differences attribut- 

 able to treatment. 



Field studies also included a series of 

 tests to deternnine possible effects on wild- 

 life of chemical control of Eurasian water- 

 milfoil with 2,4-D. Field application of 

 granular formulations of 2,4-D as high as 

 120 pounds acid equivalent per acre did not 

 kill caged oysters, crabs, clams, or fish. 

 Animals now are being analyzed for herbi- 

 cidal residues. In one trial, however, decay 

 of treated vegetation reduced oxygen in the 

 water to the extent that both caged and un- 

 caged animals died. 



Tissues from several deer and one ante- 

 lope collected in Montana and Wyoming fol- 

 lowing treatment of forest and range areas 

 with DDT and aldrin, respectively, were 

 found to contain varying amounts of pesti- 

 cide residues, the greatest amounts being 

 present in the fat. 



A long-term field investigation of the 

 effects on wildlife of Sevin was begun in 

 July 1961 at Lostwood National Wildlife 



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