But summer wanes, and autumn approaches.  The songsters of the seed-time are silent at the reaping of the harvest.  Other minstrels take up the strain.  It is the heyday of insect life.  The day is canopied with musical sound.  All the songs of the spring and summer appear to be floating, softened and refined, in the upper air.  The birds, in a new but less holiday suit, turn their faces southward.  The swallows flock and go; the bobolinks flock and go; silently and unobserved, the thrushes go.  Autumn arrives, bringing finches, warblers, sparrows, and kinglets from the north.  Silently the procession passes.  Yonder hawk, sailing peacefully away till he is lost in the horizon, is a symbol of the closing season and the departing birds. 1863.

II

IN THE HEMLOCKS

Most people receive with incredulity a statement of the number of birds that annually visit our climate.  Very few even are aware of half the number that spend the summer in their own immediate vicinity.  We little suspect, when we walk in the woods, whose privacy we are intruding upon,—­what rare and elegant visitants from Mexico, from central and South America, and from the islands of the sea, are holding their reunions in the branches over our heads, or pursuing their pleasure on the ground before us.

I recall the altogether admirable and shining family which Thoreau dreamed he saw in the upper chambers of Spaulding’s woods, which Spaulding did not know lived there, and which were not put out when Spaulding, whistling, drove his team through their lower halls.  They did not go into society in the village; they were quite well; they had sons and daughters; they neither wove nor spun; there was a sound as of suppressed hilarity.

I take it for granted that the forester was only saying a pretty thing of the birds, though I have observed that it does sometimes annoy them when Spaulding’s cart rumbles through their house.  Generally, however, they are as unconscious of Spaulding as Spaulding is of them.

Walking the other day in an old hemlock wood, I counted over forty varieties of these summer visitants, many of the common to other woods in the vicinity, but quite a number peculiar to these ancient solitudes, and not a few that are rare in any locality.  It is quite unusual to find so large a number abiding in one forest,—­and that not a large one,—­most of them nesting and spending the summer there.  Many of those I observed commonly pass this season much farther north.  But the geographical distribution of birds is rather a climatical one.  The same temperature, though under different parallels, usually attracts the same birds; difference in altitude being equivalent to the difference in latitude.  A given height above sea-level under the parallel of thirty degrees may have the same climate as places under that of thirty-five degrees, and similar flora and fauna.  At the head-waters of the Delaware, where