Age-Class Determination of Ring-Necked Ducks

A quantitative technique was developed to distinguish adult from yearling ring-necked ducks (Aythya collaris) during the breeding season using wing feather criteria. This method requires removal and measurement of the 5th secondary (S 5) and 12th greater secondary covert (GSC 12). Bursal and other p...

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Veröffentlicht in:	The Journal of wildlife management 1986-07, Vol.50 (3), p.442-445
Hauptverfasser:	Hohman, William L., Cypher, Brian L.
Format:	Artikel
Sprache:	eng
Schlagworte:	Age structure Animal and plant ecology Animal, plant and microbial ecology Aviculture Aythya collaris Biological and medical sciences Breeding Breeding seasons Ducks Feathers Female animals Fundamental and applied biological sciences. Psychology General aspects Male animals Waterfowl Yearlings
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Beschreibung
Zusammenfassung:	A quantitative technique was developed to distinguish adult from yearling ring-necked ducks (Aythya collaris) during the breeding season using wing feather criteria. This method requires removal and measurement of the 5th secondary (S 5) and 12th greater secondary covert (GSC 12). Bursal and other plumage characteristics were evaluated for use in the field during the breeding season. Cloacal characteristics are of no value in distinguishing adult and yearling males after arrival on breeding areas (Apr), but bursal depth > 10 mm is characteristic of yearling females into their 1st breeding season. Although not all adult females have white head feathers (e.g., flecking), the presence of flecking on mature females strongly indicates adult status.
ISSN:	0022-541X 1937-2817
DOI:	10.2307/3801101