Tiny, nondescript warbler of mesquite woodlands and shrubbery. Plain gray with a whiter belly, faint white eyering, and rufous rump. Rufous crown patch is usually difficult to see. Active, constantly flitting around in brushy areas. Listen for sweet song similar to Yellow Warbler, but typically including sharper notes at the end. Mainly breeds in the southwest U.S.; departs breeding grounds early in summer and migrates to the Pacific slope of Mexico (rarely as far south as Oaxaca) for the winter. Most similar to Virginia’s Warbler, but Lucy’s totally lacks yellow. Also compare with Verdin, but note bill shape.