Food habits and distribution of wintering canvasbacks, Aythya valisineria, on Chesapeake Bay

Estuaries
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Abstract

Baltic clams (Macoma balthica) were the predominant food items of 323 canvasbacks (Aythya valisineria) collected throughout Chesapeake Bay during 1970–1979. Natural vegetation constituted 4% of the food volume. Widgeongrass (Ruppia maritima) and redhead grass (Potamogeton perfoliatus) constituted the greatest percent volume and frequency of occurrence among the plant species, whereas wild celery (Vallisneria americana) constituted only a trace of the food volume. These results contrast with historical records of food habits of canvasbacks in Chesapeake Bay. Canvasback population estimates during the 1970’s were examined to detect annual and seasonal changes in distribution. Linear regression analyses of winter canvasback populations in the bay showed a significant decline in the upper-bay and middle-bay populations, but no significant changes in the lower-bay and Potomac River populations. The changes in winter distribution and abundance of the canvasback appear related to changes in natural food availability, which is the result of altered environmental conditions.

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Publication type Article
Publication Subtype Journal Article
Title Food habits and distribution of wintering canvasbacks, Aythya valisineria, on Chesapeake Bay
Series title Estuaries
DOI 10.2307/1351718
Volume 11
Issue 1
Year Published 1988
Language English
Publisher Springer
Contributing office(s) Patuxent Wildlife Research Center
Description 11 p.
First page 57
Last page 67
Country United States
State Maryland, Virginia
Other Geospatial Chesapeake Bay
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