| Abstract: | A technique was developed to distinguish yearling from adult canvasbacks (Aythya valisineria) in the field during spring on the basis of white flecking on the distal ends of selected wing feathers. Covert feathers from adults had well-defined vermiculation patterns whereas feathers from yearlings lacked such markings. These age-related characters were confirmed by paired comparisons of feathers from the same captive birds in consecutive years and by discriminant analysis of feathers using densitometric measurements from known-age wild birds. Reflective densitometric measurements of greater secondary coverts for females and males were significantly different between 1- and 2-year-old and between 2- and 3-year-old canvasbacks. Greater secondary coverts were the best feathers for recognizing age-classes of males and females. Densitometric values indicate low variability among different observers and within samples. |
| Genre: | Article |
| ProdID: | 1001268 |
| Citation Author: | Serie, J. R.; Trauger, D. L.; Doty, H. A.; Sharp, D. E. |
| Citation Contributing Office: | Northern Prairie Wildlife Research Center |
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| Citation End Page: | 904 |
| Citation Issue: | 4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Wildlife Management |
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| Citation Number Of Pages: | 10 |
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| Citation Phsyical Description: | p. 894-904 |
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| Citation Search Results Text: | Age-class determination of canvasbacks; 1982; Article; Journal; Journal of Wildlife Management; Serie, J. R.; Trauger, D. L.; Doty, H. A.; Sharp, D. E. |
| Citation Start Page: | 894 |
| Citation Volume: | 46 |
| Citation Year: | 1982 |
| Type: | citation/reference |
| Text: | Age-class determination of canvasbacks; 1982; Article; Journal; Journal of Wildlife Management; Serie, J. R.; Trauger, D. L.; Doty, H. A.; Sharp, D. E. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Fri, 1 Jan 1982 00:00 -0600 |
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