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Aging and Sexing Criteria for Ohio Ruffed Grouse
Jeffrey A. Davis
The Journal of Wildlife Management
Vol. 33, No. 3 (Jul., 1969), pp. 628-636
Stable URL: http://www.jstor.org/stable/3799387
Page Count: 9
You can always find the topics here!Topics: Grouse, Immatures, Diameters, Feathers, Animal wings, Birds, Female animals, Age, Chickens, Wild birds
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Objective means for aging and sexing ruffed grouse (Bonasa umbellus) were developed by taking measurements on approximately 1,900 sets of wings and tails. The examination of 114 carcasses of known age and sex support the accuracy of the criteria established. Feather measurements found employable for separating adults and immatures of either sex are, in descending order of usefulness: primary (P) 9 calamus diameter, mid-rectrix length, P9 length, mid-rectrix calamus diameter. Despite subjectiveness, P10 tip contour and primary sheathing are valuable criteria which should supplement measurements. Nearly 99 percent of all aged specimens can be sexed by mid-rectrix length. Criteria of secondary value in sexing are mid-rectrix calamus diameter, P9 and P8 length, and a refinement of the tail-band method. Additional plumage characteristics found to be of little or no value for aging and sexing by the multiple-criteria technique are reported. Geographical variation in feather size limits the validity of separation points between classes to a given area.
The Journal of Wildlife Management © 1969 Wiley