Facts About Owls: Silent Hunters of the Night

Owls have fascinated people for thousands of years, appearing in myths as symbols of wisdom or omens. Real owls are remarkable predators whose bodies are finely adapted for hunting at night.

Key takeaways

• There are over 200 species of owls, living on every continent except Antarctica.
• Owls fly almost silently thanks to special feathers.
• Their hearing is exceptionally sensitive, and some can locate prey in total darkness.
• Their eyes are tube-shaped and fixed, so they turn their heads instead.
• The "wise owl" idea comes from mythology, not science.

A large family

Owls belong to the order Strigiformes. They range from the tiny elf owl, about the size of a sparrow, to the great grey owl and Eurasian eagle-owl, which are among the largest. They live in forests, grasslands, deserts, farmland and even cities. Most are nocturnal, though some, such as the northern hawk-owl and snowy owl, are active in daylight.

Silent flight

Most hunting owls have soft, fringed feathers. The leading edge of the wing is serrated like a comb, and the trailing edge is frayed. These features break up the air turbulence that produces noise, and a velvety surface on the feathers also muffles sound. The result is flight so quiet that prey often cannot hear the owl approaching, and the owl can hear its prey over the sound of its own wings.

Powerful hearing

An owl's face is shaped like a dish, called the facial disc, which funnels sounds toward the ears. In some species, such as barn owls and some others, the ears are placed asymmetrically on the head, at slightly different heights. This difference helps the brain pinpoint the direction and height of a sound. Experiments have shown that barn owls can catch mice in complete darkness using hearing alone.

Eyes that do not move

Owls' eyes are large and tube-shaped, giving excellent light-gathering ability and good night vision. The cost is that their eyes are fixed in their sockets and cannot swivel, so owls turn their entire heads. They have 14 neck vertebrae, twice as many as humans, and special blood vessel arrangements that allow them to rotate the head up to about 270 degrees without cutting off blood flow to the brain. They cannot turn their heads all the way around, despite the myth.

Hunting and diet

Owls are carnivores that eat small mammals such as mice and voles, as well as birds, insects, fish and other prey, depending on the species. They swallow prey whole or in large pieces and later cough up pellets containing indigestible fur and bones. Scientists and students dissect these pellets to learn what the owl has eaten.

Nesting

Owls generally do not build nests. Many use tree holes, old nests of other birds, cliff ledges or buildings. Barn owls often nest in barns and church towers. Eggs are laid at intervals, so chicks in one nest can differ in size.

Wisdom and folklore

In ancient Greece, the owl was associated with Athena, the goddess of wisdom, which helped create the modern symbol. In other cultures, owls have been seen as omens of death or messengers. In reality, owls are not especially intelligent compared with some other birds, such as crows, but they are superb hunters.

Helping owls

Threats include habitat loss, rodent poisons that accumulate in prey, road collisions and loss of nesting sites. Providing nest boxes, avoiding poisons and preserving old trees can help.

Species spotlight

Owls come in many shapes. The barn owl, found on every continent except Antarctica, has a pale, heart-shaped face and hunts low over fields, often nesting in barns and old buildings. The snowy owl lives in the Arctic and hunts in daylight when the sun does not set, feeding largely on lemmings. The great horned owl is a powerful North American predator that takes prey from mice to skunks and other birds. The tawny owl is widespread in Europe and the best-known source of the classic hooting. At the small end, the elf owl, found in the deserts of the south-western United States, is only about the size of a sparrow and often nests in old woodpecker holes in cactus. The burrowing owl lives in open ground and uses tunnels dug by other animals.

Calls and communication

Owls communicate mostly by sound, which suits their nocturnal habits. Hoots are used to mark territory and attract mates, and many species have a repertoire of screeches, whistles, barks and hisses. The familiar twit-twoo is often a duet between two tawny owls: the female gives a sharp call and the male answers with a hoot. Pairs may call back and forth to keep in contact, and young owls make begging calls. Scientists use recordings to count owls, because they are far easier to hear than see.

What pellets reveal

Owls swallow small prey whole and later cough up a compact pellet of undigested fur, feathers and bones. Because the bones are often intact, researchers can identify the species of prey. Studying pellets helps ecologists see what small mammals live in an area and how populations change over time. Pellets can be bought for schools, where students sort the bones and assemble skeletons, and this gives a hands-on lesson in food webs.

Owls and people

Owls appear in folklore around the world, sometimes as wise or magical and sometimes as omens. In conservation, they have been symbols and indicators. In North America, the northern spotted owl became the focus of debates about logging old-growth forests in the 1990s, and the species is still declining in places. Barn owls have been helped by nest boxes placed on farms, which also encourages natural control of rodents. Rodenticides that move up the food chain are a danger to owls, so using alternatives is better.

Watching owls responsibly

Owls can be rewarding to find, but disturbance can harm them. Look and listen at dusk or dawn, and learn the calls of local species. Keep a respectful distance from nests and roosts, avoid flash photography, and do not use recorded calls to lure birds, which can stress them and disrupt breeding. Join a local bird group or a guided owl walk to learn from experienced watchers.

Frequently asked questions

Can owls turn their heads all the way round?

No. They can turn about 270 degrees, which is much more than humans.

Do owls hoot?

Some species hoot, but others screech, whistle, hiss or make other calls.

Are owls blind in daylight?

No. They can see during the day too, though many are more active at night.

Do owls really say twit-twoo?

The phrase is a poetic version of the calls of tawny owls. Typically a female gives a sharp call that sounds like kewick, and a male answers with a hoot, so the twit-twoo you hear may be two birds calling to each other.

Why do owls cough up pellets?

Owls cannot digest fur, feathers and bones, which are packed into a pellet in the stomach and brought back up. This is similar to what many other birds of prey, gulls and crows do.

Can you keep an owl as a pet?

It is not recommended. Owls are wild animals with complex needs, and in many countries keeping one without a licence is illegal. If you find an injured owl, contact a licensed wildlife rehabilitator.

Sources and further reading

• Owl (Wikipedia)
• Cornell Lab of Ornithology: Barn Owl