The northern hawk-owl or northern hawk owl ("Surnia ulula") is a medium-sized true owl of the northern latitudes. It is non-migratory and usually stays within its breeding range, though it sometimes irrupts southward. It is one of the few owls that is neither nocturnal nor crepuscular, being active only during the day. This is the only living species in the genus "Surnia" of the family Strigidae, the "typical" owls (as opposed to barn owls, Tytonidae). The species is sometimes called simply the hawk owl; however, many species of owls in the genus "Ninox" are also called "hawk owls".