| Abstract: | Eggshell thickness, levels of pollutant residues, and population status of the white-faced ibis (Plegadis chihi) were monitored in Texas from 1969 through 1976. Texas ibis nesting populations declined by 42%. Reproductive success apparently was limited by DDE-induced shell thinning and by dieldrin-caused mortality. Eggshells averaged 4% to 10% thinner than the pre-1943 mean thickness. Shells of numerous crushed eggs exceeded 20% thinning. Mean DDE residues in randomly collected eggs decreased from 0.94 ppm in 1970 to 0.25 ppm in 1976. DDE was higher, averaging 2.5 ppm, in thin-shelled eggs. DDE was negatively correlated with shell thickness. Dieldrin and PCB residues increased slightly from 1970 to 1976, but neither was correlated significantly with shell thickness. Residues in brains of many dead and dying ibises collected during years of extreme reproductive failure, 1970 and 1973, contained between 5 and 25 ppm dieldrin. Ibises were exposed to aldrin and dieldrin by feeding in rice fields where aldrin-treated rice seed was planted. Improved nesting success in 1976 may have been related to declining residues of DDE and to the discontinued use of aldrin in rice fields. |
| Genre: | Article |
| ProdID: | 5222065 |
| Citation Author: | King, K.A.; Meeker, D.L.; Swineford, D.M. |
| Citation Contributing Office: | Patuxent Wildlife Research Center |
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| Citation End Page: | 240 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Southwestern Naturalist |
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| Citation Number Of Pages: | 16 |
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| Citation Phsyical Description: | 225-240 |
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| Citation Search Results Text: | White-faced ibis populations and pollutants in Texas, 1969-1976; 1980; Article; Journal; Southwestern Naturalist; King, K.A.; Meeker, D.L.; Swineford, D.M. |
| Citation Start Page: | 225 |
| Citation Volume: | 25 |
| Citation Year: | 1980 |
| Type: | citation/reference |
| Text: | White-faced ibis populations and pollutants in Texas, 1969-1976; 1980; Article; Journal; Southwestern Naturalist; King, K.A.; Meeker, D.L.; Swineford, D.M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DOCUMENT): | http://www.jstor.org/stable/3671244 |
| Date Other: | Wed, 16 Jun 2010 12:19 -0500 |
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