Owls are an order of birds of prey. Most are solitary, and nocturnal, with some exceptions (e.g. the Burrowing Owl). They are classified in the order Strigiformes, in which there are over 200 extant species. Owls mostly hunt small mammals, insects, and other birds, though a few species specialize in hunting fish. They are found in all regions of the Earth except Antarctica, most of Greenland, and some remote islands. Though owls are typically solitary, the literary collective noun for a group of owls is a parliament. The living owls are divided into two families, the typical owls, Strigidae, and the barn-owls, Tytonidae.