| 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. |
| Genre: | Article |
| ProdID: | 1001648 |
| Citation Author: | Dane, C. W.; Johnson, D. H. |
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| Citation End Page: | 263 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Wildlife Management |
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| Citation Number Of Pages: | 7 |
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| Citation Phsyical Description: | p. 256-263 |
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| Citation Search Results Text: | Age determination of female redhead ducks; 1975; Article; Journal; Journal of Wildlife Management; Dane, C. W.; Johnson, D. H. |
| Citation Start Page: | 256 |
| Citation Volume: | 39 |
| Citation Year: | 1975 |
| Type: | citation/reference |
| Text: | Age determination of female redhead ducks; 1975; Article; Journal; Journal of Wildlife Management; Dane, C. W.; Johnson, D. H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1975 00:00 -0600 |
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