After all the great labors of Audubon and Wilson, it is certain that the recent visible progress of American ornithology has by no means equalled that of several other departments of Natural History. The older books are now out of print, and there is actually no popular treatise on the subject to be had: a destitution singularly contrasted with the variety of excellent botanical works which the last twenty years have produced. Nuttall's fascinating volumes, and Brewer's edition of Wilson, are equally inaccessible; and the most valuable contributions since their time, so far as I know, are that portion of Dr. Brewer's work on eggs printed in the eleventh volume of the "Smithsonian Contributions," and four admirable articles in this very magazine.[14] But the most important observations are locked up in the desks or exhibited in the cabinets of private observers, who have little opportunity of comparing facts with other students, or with reliable printed authorities. What do we know, for instance, of the local distribution of our birds? I remember that in my latest conversation with Thoreau, last December, he mentioned most remarkable facts in this department, which had fallen under his unerring eyes. The Hawk most common at Concord, the Red-Tailed species, is not known near the sea-shore, twenty miles off,--as at Boston or Plymouth. The White-Breasted Sparrow is rare in Concord; but the Ashburnham woods, thirty miles away, are full of it. The Scarlet Tanager's is the commonest note in Concord, except the Red-Eyed Flycatcher's; yet one of the best field-ornithologists in Boston had never heard it. The Rose-Breasted Grosbeak is seen not infrequently at Concord, though its nest is rarely found; but in Minnesota Thoreau found it more abundant than any other bird, far more so than the Robin. But his most interesting statement, to my fancy, was, that, during a stay of ten weeks on Monadnock, he found that the Snow-Bird built its nest on the top of the mountain, and probably never came down through the season. That was its Arctic; and it would probably yet be found, he predicted, on Wachusett and other Massachusetts peaks. It is known that the Snow-Bird, or "Snow-Flake," as it is called in England, was reported by Audubon as having only once been proved to build in the United States, namely, among the White Mountains, though Wilson found its nests among the Alleghanies; and in New England it used to be the rural belief that the Snow-Bird and the Chipping-Sparrow were the same.