Length: 3.9-4.3 in (10-11 cm)

Blue-gray Gnatcatchers are tiny, slim songbirds with long legs; a long tail; and a thin, straight bill. They are pale blue-gray birds with grayish-white underparts and a mostly black tail with white edges. The underside of the tail is mostly white. The face is highlighted by a thin but obvious white eyering. They rarely slow down, fluttering after small insects among shrubs and trees with tails cocked.