The black-capped vireo feeds primarily on insects, particularly the adults and larvae of moths, butterflies and beetles which are plucked from plant surfaces as it hops and flutters amongst thick vegetation. It supplements this diet with seeds, particularly during the winter (6) (7).
The breeding season of the black-capped vireo takes place from March to July (6) (7). The male establishes a territory of between two and four acres, shortly after which the females arrive and select a male based on the quality of their territory (7). During this time, the male deters rivals with songs, displays and fights (6) (7).
Once a breeding pair has formed, the black-capped vireo builds a cup-shaped nest that is suspended from the fork of a branch, up to two metres off the ground (4). This impressive structure takes two to three days to complete (4). A day after completion of the nest, the female lays the first egg, and will lay a further egg each subsequent day (4), until three or four eggs have been laid (6). Both adults incubate the eggs for 14 to 17 days (4) and share the task of feeding the new chicks (6), until they leave the nest 10 to 12 days after hatching (4). The black-capped vireo has an average lifespan of five to six years (6).