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Reproduction in a Population of Herring Gulls (Larus argentatus) Contaminated by DDT
J. A. Keith
Journal of Applied Ecology
Vol. 3, Supplement: Pesticides in the Environment and Their Effects on Wildlife. (Jun., 1966), pp. 57-70
Published by: British Ecological Society
Stable URL: http://www.jstor.org/stable/2401445
Page Count: 14
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1. In Larus argentatus colonies in north-western Lake Michigan, nine apparently alive whole eggs averaged 19 ± 3 wet-weight ppm of DDT, 202 ± 34 of DDE, and 6.0 ± 0.9 of TDE. Ten dead egg tended to have higher concentrations. 2. In 115 nests, 30-35 % of the eggs died, an exceptional mortality, which occurred rather evenly throughout embryonic life. 3. Chicks hatching from the surviving eggs had a high, but not an exceptionally high, mortality prior to fledging. 4. Whole carcasses of three chicks that died when 1 week old contained 35-48 wet-weight ppm of DDT, 308-365 of DDE, and 10-16 of TDE. Five healthy chicks in their sixth week averaged these wet-weight ppm of DDT plus DDE plus TDE; 1.9 ± 0.7 in their brains, 7.0 ± 2.1 in breast muscle, and 180 ± 22 in body fat. 5. Overall success in 115 nests was 0.3-0.4 fledged young per adult pair.
Journal of Applied Ecology © 1966 British Ecological Society