worldgeography

owl

Owls are divided into two families: the true (or typical) owl family, Strigidae, and the barn owl and bay owl family, Tytonidae.
Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish.
They are found in all regions of the Earth except the polar ice caps and some remote islands.

Antonomy
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’ asymmetrically placed ear cavities.
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.
Owls have binocular vision, but they must rotate their entire heads to change the focus of their view because, like most birds, their eyes are fixed in their sockets.
Owls are farsighted and cannot clearly see anything nearer than a few centimetres 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 far vision, particularly in low light, is exceptionally good.

Behaviour

Most owls are nocturnal, actively hunting their prey in darkness.
Several types of owls are crepuscular—active during the twilight hours of dawn and dusk; one example is the pygmy owl (Glaucidium).
A few owls are active during the day, also; examples are the burrowing owl (Speotyto cunicularia) and the short-eared owl (Asio flammeus).

Much of the owls’ hunting strategy depends on stealth and surprise.
Owls have at least two adaptations that aid them in achieving stealth.
First, the dull coloration of their feathers can render them almost invisible under certain conditions. Secondly, serrated edges on the leading edge of owls’ remiges muffle an owl’s wing beats, allowing an owl’s flight to be practically silent.
Some fish-eating owls, for which silence has no evolutionary advantage, lack this adaptation.

An owl’s sharp beak and powerful talons allow it to kill its prey before swallowing it whole (if it is not too big).
Scientists studying the diets of owls are helped by their habit of regurgitating the indigestible parts of their prey (such as bones, scales, and fur) in the form of pellets.
These “owl pellets” are plentiful and easy to interpret, and are often sold by companies to schools for dissection by students as a lesson in biology and ecology.

Recent phylogenetic studies place owls within the clade Telluraves, most closely related to the Accipitrimorphae and the Coraciimorphae,[39][40] although the exact placement within Telluraves is disputed.