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Owls are birds from the order Strigiformes including about 200 species of mostly solitary and nocturnal birds of prey (raptors) typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp powerful talons and feathers adapted for silent flight. Exceptions include the diurnal northern hawk-owl and the gregarious burrowing owl.

Great Horn Owl

Great Horn Owl

Great Horn Owl

Owls hunt mostly small mammals, insects and other birds, although a few species specialize in hunting fish. They are found all over the world except Antarctica and some remote islands.

Owls are divided into two families: the Strigidae family of true (or typical) owls; and the Tytonidae family of barn-owls.

Owls possess large, forward-facing eyes and ear-holes, a hawk-like beak, a flat face, and usually a conspicuous circle of feathers, a facial disc, around each eye. The feathers making up this disc can be adjusted to sharply focus sounds from varying distances onto the owls' ears.

Barred Owl

Most birds of prey have eyes on the sides of their heads, but the stereoscopic nature of the owl's forward-facing eyes permits the greater sense of depth perception necessary for low-light hunting. Although owls have binocular vision, their large eyes are fixed in their sockets - as are those of most other birds - so they must turn their entire heads to change views. They are farsighted and unable to clearly see anything within a few centimeters of their eyes. Caught prey can be felt by owls with the use of filoplumes - hairlike feathers on the beak and feet that act as "feelers". Their distance vision, especially in low light, is exceptionally good.

Owls can rotate their heads and necks as much as 270°. They have 14 neck vertebrae compared to seven in humans making their necks more flexible. Their circulatory system permits rotation without cutting off blood to the brain.

The smallest owl at 1 oz. and measuring 5” in heightis the elf owl (Micrathene whitneyi). Around the same length but slightly heavier are the lesser known long-whiskered owlet (Xenoglaux loweryi) and Tamaulipas pygmy owl (Glaucidium sanchezi). The largest owl by length is the great grey owl (Strix nebulosa), around 28” on average and can reach 33 “. The heaviest and largest winged owls are two similarly sized eagle owls; the Eurasian eagle-owl (Bubo bubo) and Blakiston's fish owl (B. blakistoni). These two species are on average about 1” shorter in length than the great grey but both can attain a wingspan of 6.6’ and a weight of 10 lb. in the largest females.

Young Screech Owl

Young Screech Owl

Different species of owls produce different sounds that aids owls in finding mates or announcing their presence to potential competitors. It also aids ornithologists and birders in locating these birds and distinguishing species.

Owl plumage is generally cryptic, although several species have facial and head markings, including facemasks, ear tufts, and brightly colored irises. These markings are generally more common in species inhabiting open habitats, and are used in signaling other owls in low-light conditions.

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