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USGS · 1001268

Age-class determination of canvasbacks

Jerome R. Serie·David L. Trauger·Harold A. Doty·David E. Sharp
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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.

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Jerome R. Serie, David L. Trauger, Harold A. Doty, David E. Sharp. 1982. Age-class determination of canvasbacks. https://doi.org/10.2307/3808222

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