Читать книгу The Migration of North American Birds (1935) - Frederick Charles Lincoln - Страница 11

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It is known that at any given point many species leave in fall and return in spring. Since bird banding has had such wide application as a method of study, it is known also that in some species one of the parent birds (rarely both) frequently returns and nests in the same tree, bush, or box that held its nest in the previous season (fig. 1. One ordinarily thinks of the world of birds as quiescent during two seasons each year, at nesting time and in winter. For individual species this is obviously the case, but when the entire avifauna of the continent is considered it is found that there are at almost all periods some latitudinal movements.

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Figure 1.—The bluebird may return regularly year after year to nest in the same hole or box that was occupied in previous seasons.