The vireos are a group of migratory warbler-like birds of the Americas. Birds of the tree canopy, they have relatively dull plumage, a robust build and heavy bills. Although they feed largely on insects many also take fruit when it is available. Vireos are generally monogamous, and all build a pendant shaped nest from bark and leaves and bound together by spider silk. The more migratory species of North America are sometimes blown off course and occasionally turn up on the west coast of Britain.