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Toxicity of Lead and Proposed Substitute Shot to Mallards

Special Scientific Report -- Wildlife 183

1618_Longcore.pdf and 1618_Longcore_OCR.pdf
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Abstract

Poisoning of North American waterfowl resulting from the ingestion of lead shot by ducks, geese, and swans causes an estimated annual mortality of 2 to 3% of the population (Bellrose 1959). To alleviate this problem the search for a suitable substitute for lead has been underway since the early 1950's. Proposed substitutes for lead shot were evaluated in a series of acute toxicity tests with pen-reared mallards (Anas platyrhynchos). Most candidate materials were as toxic to ducks as commercial lead shot. Coating or alloying lead with other metals only delayed mortality among dosed ducks. The reputedly 'disintegrable' lead shot with the water-soluble binder and the lead containing biochemical additives were also as toxic to mallards as the commercial lead shot. Mortality was not significantly different among lead-dosed adult or first-year hen and drake pen-reared mallards; lead-dosed adult, wild mallards of both sexes; and lead-dosed adult, male black ducks (Anas rubripes). The ingestion of one lead shot, size 4, by each of 80 pen-reared mallards caused an average 19% mortality. The presence and type of grit in the gizzard had a measurable effect on erosion of ingested shot and on shot retention among dosed mallards. Significantly fewer lead-dosed ducks died when fed crushed oystershell grit than when fed either quartz grit or no grit.

Additional Publication Details

Publication type:
Report
Publication Subtype:
Federal Government Series
Title:
Toxicity of Lead and Proposed Substitute Shot to Mallards
Series title:
Special Scientific Report -- Wildlife
Series number:
183
Year Published:
1974
Language:
English
Publisher:
U.S. Fish and Wildlife Service
Contributing office(s):
Patuxent Wildlife Research Center
Description:
iv, 23