File:Characters of age, sex and sexual maturity in Canada geese (1962) (20590278735).jpg

Title: Characters of age, sex and sexual maturity in Canada geese
Identifier: charactersofages49hans (find matches)
Year: 1962 (1960s)
Authors: Hanson, Harold C. (Harold Carsten), 1917-
Subjects: Canada goose; Birds
Publisher: Urbana
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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Text Appearing Before Image:
PLUMAGE CHARACTERS The tail feathers, the priinan featliers of the wing, and the feathers of the breast and beliy are all use- ful in determining age in Canada geese. Tail Feathers.—TTic frayed or notched tip in the tail feathers of immature waterfowl, first shown to be a character of age by Beebe & Crandall (1914) and later described by Schi0!er (1924) and others, has been widely employed by waterfowl biologists as a criterion of age (Elder 1946:98; Hanson 1949:179), Fig. 2. In most instances, the tail feathers of the first postnatal plumage may be readily differentiated from those of the adult plumage by their narrower, more tapered outline and their less in- tense pigmentation. During the winter, the tail feath- ers of the immature plumage are gradually replaced by the longer, broader, and more deeply pigmented tail feathers characteristic of adult plumage. The tail feathers are generally replaced two at a time, begin- ning with the central pair. In immature Canada geese in southern Illinois, replacement of tail feathers in winter is largely limited to the c-entral two or three pairs. Observations made in early May, 1959, on the breeding grounds of these geese in northern Ontario, revealed that the tail feather criterion of age could be employed, with nearly comparable accuracy, during
Text Appearing After Image:
lij;. 2. — Tail fiatliors of Canatla geese: A and B, immatdrcs in winter; C, adult in winter; D, immature in earlv Mav. .\ noUluxl tip is evident in most of tlie feathers of tlie ininiatiiros.

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