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Age determination of female redhead ducks

Journal of Wildlife Management
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Abstract

Eighty-seven fall-collected wings from female redhead ducks (Aythya americana) were assigned to the adult or juvenile group based on 'tertial' and 'tertial covert' shape and wear. To obtain spring age-related characters from these fall-collected groupings, we considered parameters of flight feathers retained until after the first breeding season. Parameters measured included: markings on and width of greater secondary coverts, and length, weight, and diameter of primary feathers. The best age categorization was obtained with discriminant analysis based on a combination of the most accurately measured parameters. This analysis, applied to 81 wings with complete measurements, resulted in only 1 being incorrectly aged and 3 placed in a questionable category. Discriminant functions used with covert markings and the three 5th primary parameters were applied to 30 known-age juvenile, hand-reared redhead females, 28 were correctly aged, none was incorrectly aged, and only 2 were placed in the questionable category.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Age determination of female redhead ducks
Series title Journal of Wildlife Management
Volume 39
Issue 2
Year Published 1975
Language English
Description 8 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Wildlife Management
First page 256
Last page 263