ALMOST everywhere in the United States this active little bird may be found, inhabiting chiefly open, high woods. Often he may be seen along streams, skipping and darting about among the topmost branches of the trees, his long tail elevated and jerking in wren-like fashion, always moving about and ever uttering his wheezy, squeaky notes. Ridgway says that during the breeding season the male has a varied song of considerable power, but lacking in sweetness, and uttered in an erratic manner, portions of it suggesting a weak imitation of the Catbird's medley.

It is as a nest builder that the Gnatcatcher is best known. Davie, whose life study has been nests and eggs, says that as a work of beauty and ingenious architectural design the nest of this bird has few equals in this country. On the whole, it is a rather frail structure, usually built in the small upright twigs or saddled on the horizontal limbs of trees at heights ranging from ten to fifty feet, but generally at an elevation of about fifteen or twenty feet. The typical nest has high, compact walls, contracted at the brim, and gracefully turned; the interior is deeply cupped, and the exterior is beautifully ornamented with lichens. The opening is always at the top. Often the nest is attached to a limb of the same diameter as itself, thus appearing as a knot or other excrescence. If, as Baskett says, "there can be no doubt that a bird may take delight in the skill of its work and the beauty of its home, as well as in its plumage," the dainty residence of the Blue-gray Gnatcatcher would indicate that the pretty little bird experiences a great amount of pleasure indeed. She lines her nest with soft, downy materials—cotton-like substances of withered blossoms and the silky down of the milkweed—fine, wiry grasses, horsehair, and an occasional feather from her own breast. In this she lays four or five eggs of greenish or bluish white, speckled with chestnut.

Col. Goss describes this bird as as much at home in the shrubby bushes on the hillsides or mesquite growths on the plains, as within the tree-tops of the heavily timbered bottom lands; a nervous, restless species that, in their quest of insect life, nimbly skip from branch to branch, with partially spread wings and flirting tails, held more or less erect, now and then darting like a flash into the air to catch the passing flies; a tireless picture of bustling energy, that only ceases with the day. The soft, warbling love song is varied, tender, and full of melody, but so low, the hearer must stop to listen in order to fully catch its silvery tones.