IUCN Conservation Status: Least Concern
A furtive bird of forest edges and thickets, MacGillivray's Warbler breeds across much of the Pacific Northwest and the Rocky Mountains. In appearance, voice, habits, and winter range, it resembles its close relative, the Mourning Warbler, but the breeding ranges of the two species do not overlap.
Song is a rolling series of churring syllables, similar to song of Mourning Warbler but more complex, longer, and higher. Call is a harsh chip, or a high, ventriloquial chip.