5 inches long. The Black-throated Green Warbler has bright olive-green upperparts and a yellow face with a greenish ear patch. It has a dark wing with two white bars. The male has a black chin, throat, and breast, with bold streaks on the flanks of the white belly. Occasionally the belly will show a tinge of yellow on the flanks. The upper tail is dark with white outer tail feathers. The female is similar but with no black on the chin and reduced black on the remainder of the undersides. Immature birds usually only have black streaks on the flanks.