Читать книгу Migration of Birds (1979) - Frederick Charles Lincoln - Страница 9

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Reference material consisting of preserved bird skins with data on time and place of collection exist in many natural history museums. The essential ingredient in studying migration by this method is to have an adequate series of specimens taken during the breeding season so differences in appearance between geographically separated breeding populations of the same species can be determined. Such properly identified breeding specimens may be used for comparison with individuals collected during migration to associate them with their breeding areas (Aldrich 1952; Aldrich, Duvall, and Geis 1958). This supplies a convenient way of recognizing and referring to individuals representative of known populations wherever they may be encountered.