US EPA

2197519 

Technical Report 

Organochlorine residues in raptor eggs in the Cayuga Lake Basin, New York, USA 

Lincer, JL; Clark, RJ 

1978 

HEEP/80/08560 

25 

2 

121-128 

HEEP COPYRIGHT: BIOL ABS. Organochlorine residue burdens and eggshell thinning in the eggs of hawks and owls nesting in the Cayuga Lake Basin in central New York were compared. Except for those of the buteos (red-tailed hawk, red-shouldered hawk and broad-winged hawk), all the eggs examined contained high, but variable, DDE levels. Values in eggs of the red-tailed hawk ranged from span. Eggs of the screeh owl, American kestrel and Cooper's hawk contained intermediate mean residue levels (12-67 ppm). The highest mean DDE level and the highest DDE level in an individual egg were exhibited by the great horned owl (102 and 248, respectively). Limited data on residues are also presented for dieldrin, heptachlor epoxide and PCB (polychlorinated biphenyls). Data on eggshell thinning indicated that there had been little decrease in shell thickness for eggs of the buteos, while for eggs of the great horned owl and American kestrel shell thickness had decreased about 10%. The Copper's hawk exhibited the greatest increase in the degree of eggshell thinning (19%), and its situation may be critical. The ecological factors responsible for residue differences between hawk-owl counterparts are discussed.