Owls are widely recognized as silent hunters, but their vocal repertoire is surprisingly complex and extends far beyond the familiar “hoot.” The sounds an owl produces originate from the syrinx, the bird’s vocal organ, located deep in the respiratory tract. This structure creates sound using vibrating membranes and a self-oscillating system to modulate airflow, unlike the vocal folds found in mammals. Owls use this unique organ to generate a diverse range of calls for communication, territorial defense, and mating.
Primary Vocalizations
The “hoot” is the most recognized vocalization, serving primarily for territorial marking and attracting mates over long distances. The specific quality and pattern of the hoot varies significantly among species, acting as a species-specific identifier in the dark. For instance, the Great Horned Owl produces a deep, slow, and soft hoot, often in a five-note pattern, which has been likened to the sound of a muted bassoon.
The hoot of the Barred Owl is distinctly different, presenting as a rich baritone call often interpreted as the mnemonic phrase “Who cooks for you? Who cooks for you-all?” This rhythmic call is used for pair-bonding communication. The Barn Owl does not hoot at all, instead relying on a long, harsh, raspy shriek or scream.
The male Barn Owl uses this eerie, two-second screech to beckon a female to inspect a potential nest site. Other species use barks, whistles, or various screams for long-distance contact during the breeding season. The female Great Horned Owl’s hooting is generally higher-pitched, quicker, and longer than the male’s.
Warning and Defensive Sounds
When an owl feels threatened, its vocalizations shift from long-range communication to short-range, aggressive intimidation. A common defensive sound is the hiss, which many species produce to mimic a snake. This sound is often described as escaping air and is used to warn off intruders, especially near a nest.
The hiss is frequently coupled with an aggressive posture to maximize the frightening effect on a predator. Alarm calls or scolding sounds are also directed at enemies, such as a Great Horned Owl female growling at a squirrel near the nest. The Barn Owl may also produce a softer, wavering version of its screech, known as a purring call, when it feels mildly agitated.
These defensive sounds are designed for immediate, close-quarters threat display, indicating the owl is ready to defend itself or its young. The intensity of the vocalization often correlates directly with the level of perceived danger.
Communication Between Young and Parents
Within the family unit, owlets and their parents employ a specific set of calls focused on feeding and locating one another. The most persistent and recognizable of these is the owlet’s “begging call,” used to solicit food from the adult owls. This call is a repetitive, high-pitched vocalization, often described as a trill, whistle, or persistent screech.
For Great Horned Owlets, the begging call can sound like a loud, incessant, drawn-out shriek. Juvenile owls continue to use this sound even after leaving the nest, demanding food from their parents until they become proficient hunters.
Parent owls use softer contact calls to communicate with their nested young, ensuring the owlets know a parent is nearby or arriving with food. Female Barn Owls also use a high-pitched screech, similar to the male’s courtship call, when soliciting food from their mate.
Non-Vocal Noise Production
Not all sounds made by owls originate from the syrinx; some are mechanical noises produced by the body itself. The most common non-vocal sound is bill snapping or clacking, which is generated by rapidly striking the upper and lower mandibles together. This action produces a sharp, loud, clicking sound used as a threat display when the owl is highly agitated, often accompanying the defensive hiss.
Another mechanical noise is wing clapping, a sound produced when the carpal joints of the wings are intentionally struck together in flight. This percussive noise is heard during the courtship or territorial display flights of certain species, such as the Short-eared and Long-eared Owls.
These non-vocal sounds contrast with the near-silent flight of most owls, which is enabled by specialized serrations on their flight feathers. While owls are famous for their stealth in the hunt, they are capable of creating loud, abrupt, and mechanical noises for overt displays of aggression or courtship.