Corvids are large to very large passerines with a robust build, strong legs and all species except the pinyon jay have nostrils covered by bristle-like feathers. Many corvids of temperate zones have mainly black or blue coloured plumage; however, some are pied black and white, some have a blue-purple iridescence and many tropical species are brightly coloured. The sexes are very similar in color and size. Corvids have strong, stout bills and large wingspans. The family includes the largest members of the passerine order.