Another familiar bird here, which I never met with in the North, is the gnatcatcher, called by Audubon the blue-gray fly-catching warbler. In form and manner it seems almost a duplicate of the cat-bird, on a small scale. It mews like a young kitten, erects its tail, flirts, droops its wings, goes through a variety of motions when disturbed by your presence, and in many ways recalls its dusky prototype. Its color above is a light, gray blue, gradually fading till it becomes white on the breast and belly. It is a very small bird, and has a long, facile, slender tail. Its song is a lisping, chattering, incoherent warble, now faintly reminding one of the goldfinch, now of a miniature cat-bird, then of a tiny yellow-hammer, having much variety, but no unity, and little cadence. Another bird which has interested me here is the Louisiana water-thrush, called also large-billed water-thrush, and water-wagtail. It is one of a trio of birds which has confused the ornithologists much. The other two species are the well-known golden-crowned thrush (_Sciurus aurocapillus_) or wood-wagtail, and the Northern, or small, water-thrush (_Sciurus noveboracensis_). The present species, though not abundant, is frequently met with along Rock Creek. It is a very quick, vivacious bird, and belongs to the class of ecstatic singers. I have seen a pair of these thrushes, on a bright May day, flying to and fro between two spring runs, alighting at intermediate points, the male breaking out into one of the most exuberant, unpremeditated strains I ever heard. Its song is a sudden burst, beginning with three or four clear round notes much resembling certain tones of the clarionet, and terminating in a rapid, intricate warble. This bird resembles a thrush only in its color, which is olive-brown above, and grayish-white beneath, with speckled throat and breast. Its habits, manners, and voice suggest those of the lark.