Owls are one of the most identifiable nocturnal animals, meaning they are known for being alert at night and sleeping during the day. While not all owls are nocturnal, many are and the noises they make are often heard in rural, wooded areas where they nest. These sounds include hoots, screeches, barks, growls and shrieks. The exact sound and meaning of these noises varies by owl species.
The "hoot" is a very recognisable owl call. Great horned owls are especially known for their hooting sound, which involves two short, deep "hoo" sounds followed by a long "hooooooo." This sound is usually territorial and can be heard for several miles. Both male and female owls hoot, but male hoots are usually deeper than females. Owls usually begin hooting at dusk and will continue until about midnight. Hooting may start again briefly before dawn.
Owls will sometimes shriek when threatened. Great horned owls, for example, will emit a high-pitched note when attacking threatening animals. Barking owls have also been known to give loud screeches during breeding season. These calls are called "screaming woman" calls for their alarming similarity to a screaming lady. Screeching usually occurs briefly after dusk and right before dawn.
Some owls use a low, barking sound when surprised or frightened. This sound is given in sharp, sudden intervals to scare off threats. Frightened barks may occur any time of night depending on when the owl feels threatened. Some owls, like the Australian barking owl, give a loud "wuf wuf" noise for which they are named. These calls are often given in a volley fashion between male and female owls and may be part of a mating or location ritual. These volleys may go on for a few minutes, but don't continue the entire night.
Threatened owls have also been known to growl to deter predators. The great horned owl's growl sounds like a short, low-pitched honk from deep in the throat. Barking owls also emit a doglike snarling sound when defending their nest, but these sounds don't carry and are usually only heard at close range.
Infant owls are sometimes heard shrieking at night. Owlets operate on the same nocturnal schedule as their parents. When owls wake at night the parent will often go off to hunt, leaving the infant owls in the nest. Therefore the shrieking of infant owls can signal hunger or an attempt desire to call back their parent. Many different owl species making shrieking sounds as infants include the common barn owl, the common scops owl and the common sooty owl.