The social sparrow, alias "hairbird," alias "red-headed chipping-bird," is the smallest of the sparrows, and I believe, the only one that builds in trees. The finches, as a class, all have short conical bills, with tails more or less forked. The purple finch heads the list in varied musical abilities. Besides the groups of our more familiar birds which I have thus hastily outlined, there are numerous other groups, more limited in specimens but comprising some of our best-known songsters. The bobolink, for instance, has properly no congener. The famous mockingbird of the Southern States belongs to a genus which has but two other representatives in the Atlantic States, namely, the catbird and the long-tailed or ferruginous thrush. The wrens are a large and interesting family, and as songsters are noted for vivacity and volubility. The more common species are the house wren, the marsh wren, the great Carolina wren, and the winter wren, the latter perhaps deriving its name from the fact that it breed in the North. It is an exquisite songster, and pours forth its notes so rapidly, and with such sylvan sweetness and cadence, that it seems to go off like a musical alarm. Wilson called the kinglets wrens, but they have little to justify the name, except that the ruby-crown's song is of the same gushing, lyrical character as that referred to above. Dr. Brewer was entranced with the song of one of these tiny minstrels in the woods of New Brunswick, and thought he had found the author of the strain in the black-poll warbler. He seems loath to believe that a bird so small as either of the kinglets could possess such vocal powers. It may indeed have been the winter wren, but from my own observation I believe the ruby-crowned kinglet quite capable of such a performance. But I must leave this part of the subject and hasten on. As to works on ornithology, Audubon's, though its expense puts it beyond the reach of the mass of readers, is by far the most full and accurate. His drawings surpass all others in accuracy and spirit, while his enthusiasm and devotion to the work he had undertaken have but few parallels in the history of science. His chapter on the wild goose is as good as a poem. One readily overlooks his style, which is often verbose and affected, in consideration of enthusiasm so genuine and purpose so single.