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The Impact Of Pesticides On The White-Faced Ibis, David E. Capen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The white-faced ibis (Plegadis chihi) which nested in northern Utah was assessed as a species with a relatively low reproductive potential. Ibises normally laid either three or four eggs in a clutch and did not renest persistently, nor with good success, if initial nesting attempts failed. Evidence indicated that the birds did not breed until at least 2 years old. Competition for food, exposure to severe weather, and predation were conspicuous sources of nestling mortality. White-faced ibises usually fed in irrigated agricultural areas, where they came into direct contact with insecticides, such as DDT which was used routinely …