There are some 200 species of owl - known for their distinct calls, nocturnal habits and silent flight. These species are sorted into two basic groups, the barn owls and the true owls.The wings of an owl are finely serrated so that they can fly silently. This is to allow the owl to approach its prey silently without it hearing it first, and so that they owl itself can hear its prey over its own sounds.
The eyes of owls are adapted to be like a pair of binoculars. They are fixed in place, allowing for detailed long distance vision for hunting, but this does mean their close range vision is very poor. To look around the owl has to move its entire head, it is a common myth that they can turn their head all the way around, it actually only rotates around 270 degrees horizontally, and around 90 degrees vertically. To be able to do this the owl has extra bones in their neck. Most vertebrates, including us, only have 7 vertebrae in their neck, whereas an owl has 14.
Owl Eyes
Although there are exceptions, eye colour tends to indicate what time of day the owls prefer to be active.
Orange Eyes: Most owls that sport orange eyes are active around dawn and dusk, which is known as being crepuscular.
Dark Brown or Black Eyes: Owls that have dark brown or black eyes typically are nocturnal, which means they prefer to hunt at night. The dark colour doesn't help the owls see in the dark, but it might help camouflage them better than brighter-coloured eyes. Owls with dark eyes, such as the northern spotted owl, barred owl and barn owl, follow the trend of hunting at night, although they are sometimes seen out in daylight, especially on cloudy days.
Yellow Eyes: Yellow eyes often appear on owls who are diurnal – they prefer to hunt during the day. The great grey owl is an example of a diurnal owl with yellow eyes.
To cope with the lack of short range vision they have a group of sensitive feathers, called crines, around their beak. These sensitive feathers are used to locate dead prey.
Owls have very sensitive hearing, used to locate prey either hidden under snow or other coverings, or to hunt in the dark. Owl’s ears are holes hidden beneath the feathers, one further up than the other, allowing the owl to pinpoint the location of a sound. This ability lets them build a sort of sound map and locate prey, often in complete darkness, by sound alone. The feathers of an owl’s face help with this hearing, by forming a facial disk, a disk of feathers used like a satellite dish to help point any sound towards these ears.
See also: Ashy-faced owl, Barn owl, Bengal eagle-owl, Black-banded owl, Brown wood owl, Burrowing owl, Eagle-owl, Ferruginous Pygmy Owl, Great grey owl, Great Horned owl, Long-eared owl, Northern hawk-owl, Northern white faced cops owl, Pacific screech owl, Pearl spotted owlet, Rock eagle owl, Snowy Owl, Spectacled owl, Southern Boobook owl, Striped owl, Tawny frogmouth owl, Tawny owl, Ural Owl, Verreaux's eagle-owl, also known as the milky eagle owl or giant eagle owl, White-faced scops owl
