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Feeding ecology and development of juvenile black ducks in Maine

Auk

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Abstract

Data from 41 juvenile Black Ducks (Anas rubripes) collected in the Penobscot River valley of Maine from June through August 1974-76 were used to estimate the proportion of aquatic invertebrates in the prefledging diet and the allometric growth rates of the tarsi, flight muscles, and alimentary system. The proportion of aquatic invertebrates in the diet of downy and partially feathered juveniles averaged 88 and 91% of dry weight, but decreased to 43% for fully feathered young. The most important invertebrate food organisms for juvenile Black Ducks were asellid isopods, molluscs, nymphs of Ephemeroptera and Odonata, and larvae of Coleoptera, Trichoptera, and Diptera. A high proportion of invertebrates was consumed during the period of fastest absolute and relative growth. Estimation of allometric growth rates with the power formula (Y = a 'X b) showed that (1) the legs were relatively large at hatching and developed slowly; (2) the flight muscles, which were relatively small at hatching, grew slowly until the 4-week period preceding fledging, when they increased as the 4.75 power of body weight; and (3) growth of the liver and gizzard was approximately proportional to body weight. The data support Ricklefs' thesis that delayed functional maturity of the wings permits an increase in the overall growth rate of waterfowl.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Feeding ecology and development of juvenile black ducks in Maine
Series title:
Auk
Volume
96
Issue:
4
Year Published:
1979
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
737-745
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Auk
First page:
737
Last page:
745
Number of Pages:
9