A tiny, long-tailed, thin-billed songbird. Soft blue-gray above and whitish below, with a thin white eyering. Breeding males have a black band across the forehead. Forages actively for insects, often actively twitching its long tail. Can be found singly or in pairs, sometimes with mixed flocks of other songbirds, especially during migration. Two populations: Eastern birds breed in deciduous woodlands, often near water; western birds typically breed in drier, brushier habitats. Winters from the southern U.S. to northern Central America. Compare with Black-tailed Gnatcatcher, especially the tail pattern from below: Blue-gray is mostly white, with very limited black. Also very similar to Black-capped Gnatcatcher on the wintering grounds in West Mexico; Blue-gray has a higher-pitched call.