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Influence of nutrients on feed intake and condition of captive canvasbacks in winter

Journal of Wildlife Management

also presented at the Breeding Waterfowl Symposium, Winnepeg, Manitoba, 1987
By:
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Abstract

Dramatic changes in the food habits and distribution of canvasbacks (Aythya valisineria) in Chesapeake Bay during the 1970's generated a need to evaluate the nutritional value of food items and the requirements of this species on its wintering grounds. Groups of captive canvasbacks were maintained ad libitum on 5 diets during the winters of 1978-79 and 1979-80 to evaluate the effects of varying protein and energy levels on feed intake and condition. Feed intake during the 1979-80 winter was 42% greater for those ducks fed the low energy (1,543 kcal/kg) diet than for those fed the high energy (3,638 kcal/kg) diet. Canvasbacks fed the high energy diet, however, consumed 317 kcal/bird day, whereas those fed the low energy diet consumed only 191 kcal/bird day. Body weight of males and females did not differ among groups fed different diets, but there were seasonal differences (P < 0.05) for both sexes aggregated across diets. Data from this study indicate that canvasbacks may be unable to adjust intake rates to compensate for low energy foods and subsequently may store less fat or modify behavior. However, decreased weight, feed intake, and activity of ducks fed ad libitum rations occurred in mid-winter irrespective of diet quality and appeared to be an endogenous component of their annual cycle that persists in captivity. These changes apparently have a selective advantage of increasing the probability of survival in ducks by decreasing energy expenditure during periods of winter stress.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Influence of nutrients on feed intake and condition of captive canvasbacks in winter
Series title:
Journal of Wildlife Management
Volume
50
Issue:
3
Year Published:
1986
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
427-434
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
427
Last page:
434
Number of Pages:
8