Occasionally in the earlier part of May I find the woods literally swarming with warblers, exploring every branch and leaf, from the tallest tulip to the lowest spice-bush, so urgent is the demand for food during their long northern journeys. At night they are up and away. Some varieties, as the blue yellow-back, the chestnut-sided, and the Blackburnian, during their brief stay, sing nearly as freely as in their breeding-haunts. For two or three years I have chanced to meet little companies of the bay-breasted warbler, searching for food in an oak wood on an elevated piece of ground. They kept well up among the branches, were rather slow in their movements, and evidently disposed to tarry but a short time. The summer residents here, belonging to this class of birds, are few. I have observed the black and white creeping warbler, the Kentucky warbler, the worm-eating warbler, the redstart, and the gnat-catcher, breeding near Rock Creek. Of these the Kentucky warbler is by far the most interesting, though quite rare. I meet with him in low, damp places in the woods, usually on the steep sides of some little run. I hear at intervals a clear, strong, bell-like whistle or warble, and presently catch a glimpse of the bird as he jumps up from the ground to take an insect or worm from the under side of a leaf. This is his characteristic movement. He belongs to the class of ground warblers, and his range is very low, indeed lower than that of any other species with which I am acquainted. He is on the ground nearly all the time, moving rapidly along, taking spiders and bugs, overturning leaves, peeping under sticks and into crevices, and every now and then leaping up eight or ten inches to take his game from beneath some overhanging leaf or branch. Thus each species has its range more or less marked. Draw a line three feet from the ground, and you mark the usual limit of the Kentucky warbler's quest for food. Six or eight feet higher bounds the usual range of such birds as the worm-eating warbler, the mourning ground warbler, the Maryland yellow-throat. The lower branches of the higher growths and the higher branches of the lower growths are plainly preferred by the black-throated blue-backed warbler in those localities where he is found. The thrushes feed mostly on and near the ground, while some of the vireos and the true flycatchers explore the highest branches. But the warblers, as a rule, are all partial to thick, rank undergrowths. The Kentucky warbler is a large bird for the genus and quite notable in appearance. His back is clear olive-green, his throat and breast bright yellow. A still more prominent feature is a black streak on the side of the face, extending down the neck.