Black-capped Vireos have a striking face pattern: a blackish head with bold white “spectacles” and white throat. The upperparts are olive green with two white wingbars; the underparts are whitish with yellowish flanks. In males the head is jet black; females and immatures are less vividly colored overall. First-year males have a grayish nape.
Stays low in vegetation and hops rapidly between branches to examine twigs and leaves for insect larvae, then flies rapidly a short distance to the next shrub, tree, or thicket to continue searching. Males sing through the early part of the nesting season, even at midday, sometimes from the tops of bushes and small trees but often from concealed perches in scrubby vegetation.