Uncommon gnatcatcher in arid scrubby areas of s. TX. Habitat is a great clue to identity, but look for black undertail with white tips. Breeding ♂ has striking black cap. In winter, this is reduced to short black line above eye. ♀ and imms have browner upperparts. Tail more graduated than BGGN giving rounded appearance. Bill narrower-based and shorter. Multiple calls: hissing ‘psss,’ ‘chips,’ and others.