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

Estuaries

Based in part on paper, 'Availability and utilization of canvasback food organisms in Chesapeake Bay,' presented at Atlantic Estuarine Research Society, Rehoboth Beach, DE, 1976 and Distribution and abundance of canvasbacks in Chesapeake Bay in relation to food organisms, at Atlantic Estuarine Research Society, Cape May, NJ, 1976. 3658_Perry.pdf
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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.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Food habits and distribution of wintering canvasbacks, Aythya valisineria, on Chesapeake Bay
Series title:
Estuaries
Volume
11
Issue:
1
Year Published:
1988
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
57-67
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Estuaries
First page:
57
Last page:
67
Number of Pages:
11