Rocs are equally comfortable over land and sea. While they are capable of sleeping in the air as they soar solo across great ranges in search of food, they generally return home to the mountains to roost and procreate. They prefer rocky crags that are completely inaccessible by terrestrial means, building vast nests of tree trunks and ruined masonry. Once a decade, a mated pair lays a clutch of 3-5 eggs and raises its young. Outside of mating, rocs are extremely antisocial, and may attack others of their kind in vicious aerial battles in order to establish their territorial boundaries. When a nest contains eggs or chicks, parents trade off in their long-ranging flights, with one restricting its wanderings to within a 10-mile radius of the nest.