"The cavity nest is a chamber, typically in living or dead wood, but sometimes in the trunks of tree ferns[59] or large cacti, including saguaro.[59][60] In tropical areas, cavities are sometimes excavated in arboreal insect nests.[61][62] A relatively small number of species, including woodpeckers, trogons, some nuthatches and many barbets, can excavate their own cavities. Far more species—including parrots, tits, bluebirds, most hornbills, some kingfishers, some owls, some ducks and some flycatchers—use natural cavities, or those abandoned by species able to excavate them; they also sometimes usurp cavity nests from their excavating owners. Those species that excavate their own cavities are known as "primary cavity nesters", while those that use natural cavities or those excavated by other species are called "secondary cavity nesters".