These birds are sluggish and heavy warblers, preferring to spend most of their time on, or near the ground, except when singing.

MacGillivray's warbler was named by John James Audubon in honor of Scottish ornithologist William MacGillivray, although the proper credit to its discovery goes to John Kirk Townsend.

Adult MacGillivray's warblers are an olive-green color on their upperparts and dull yellow below.

Males have black heads and breasts, while females and immature birds have drab light gray heads; both males and females have broken white eye-rings.

In autumn, these birds migrate to Central America, where they stay in temperate shrublands for the winter.