True owl

True owls (typical owls) are owls of the family Strigidae.

True owl Temporal range: Early Eocene to present
Eastern screech owl
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Strigiformes
Family:	Strigidae Leach, 1820
Genera
some 25, see text
Synonyms
Striginae sensu Sibley & Ahlquist

Cross sectioned Great Grey owl specimen showing the extent of the body plumage, Zoological Museum, Copenhagen

They are one of the two families of owls, with 189 living species in 25 genera. The other family is the barn owls. True owls are found on every continent except Antarctica.

The division of owls into these two groups is quite ancient. The relationships of the owls in general are still unresolved.^[1][2]

Morphology

Typical owls vary greatly in size. The smallest is the elf owl. Its weight is a hundred times less than the largest, the Eurasian eagle owl and Blakiston's fish owl. Most owls have very similar bodies.^[3] They have large heads, short tails, and round facial circles around the eyes. Most live in trees (with a few exceptions like the burrowing owl) and get their food on the wing. The wings are large, broad, rounded and long. Like other birds of prey many owls have females that are larger than males.^[4]

They are nocturnal. Because of this the plumage is not much different between males and females. The feathers are soft and the base of each is downy. This give them silent flight. Hearing in owls is highly sensitive. The ears are asymmetrical which lets the owl localise a sound. Owls have massive eyes relative to their body size.