Page:Summer - from the Journal of Henry D. Thoreau.djvu/30

We saw many of these birds flitting about the summit, perched on the rocks and the dwarf spruces, and disappearing behind the rocks. It is the prevailing bird now on the summit. They are commonly said to go to the fur countries to breed, though Wilson says that some breed in the Alleghanies. The New York Reports make them breed in the Catskills and some other mountains of that State. This was a quite interesting discovery. They probably are never seen in the surrounding low grounds at this season. The ancestors of this bird had evidently perceived in their flight northward that here was a small piece of arctic region containing all the conditions they require, coolness and suitable food, etc., etc., and so for how long have builded here. For ages they have made their home here with the Arenaria Groenlandica and Potentilla tridentata. They discerned arctic isles sprinkled in our southern sky. I did not see any of them below the rocky and generally bare portion of the mountain. It finds here the same conditions as in the north of Maine and in the far countries, Labrador mosses, etc. . . . Now that the season is advanced, migrating birds have gone to the extreme north or to the mountain tops. By its color it harmonized with the gray and brownish-gray rocks. We felt that we were so much nearer to perennial spring and winter. . . .