Owls are birds of prey known for their large heads, upright posture, and forward-facing eyes. They are often symbols of wisdom and mystery in folklore. Found in nearly every terrestrial habitat worldwide, their success comes from specialized adaptations for a mostly solitary and nocturnal lifestyle, including silent flight and remarkable hearing, which allows them to hunt effectively in low-light conditions. Over 200 species are recognized, all belonging to the order Strigiformes, which is separated into two distinct families.
The Two Fundamental Owl Families
The classification of all owl species begins with two groups: the True Owls (family Strigidae) and the Barn Owls (family Tytonidae). Strigidae is the larger and more diverse family, containing approximately 224 species, representing the typical image of an owl. True Owls are found globally and exhibit a wide range of sizes, colors, and physical features.
The Tytonidae family contains about 20 species, including the Common Barn Owl. Barn Owls diverged evolutionarily, resulting in structural differences, particularly in the sternum and feet. This family is recognized by its distinct facial structure, which differs significantly from the round faces of the Strigidae.
Key Differences in Appearance and Hunting
The most immediate visual distinction between the two families lies in the shape of the facial disc, a concave ring of stiff feathers that collects sound. True Owls (Strigidae) generally possess a circular facial disc that funnels sound waves toward their ears. In contrast, Barn Owls (Tytonidae) are defined by a prominent, heart-shaped facial disc, which is effective at amplifying and locating sounds for precise hunting in darkness.
Another differentiating feature is the presence or absence of “ear tufts,” which are tufts of feathers on the head. These tufts are common among many True Owl species, such as the Great Horned Owl. They are used in communication, signaling emotion or alertness, and may aid in camouflage by breaking up the bird’s outline. Barn Owls typically lack these prominent feather tufts, having a smoother, more rounded head profile.
Behaviorally, the two families also differ in their activity periods. Most True Owls are strictly nocturnal, hunting only after dark. Barn Owls often exhibit crepuscular behavior, meaning they are most active during the twilight hours of dawn and dusk. Barn Owl feathers are extremely soft to maximize silent flight, though this specialization means their plumage is not as water-resistant as that of some True Owls.
Notable and Common Examples
The Great Horned Owl (Bubo virginianus) is a widely recognized example of the True Owl family (Strigidae) in the Americas. This large raptor is defined by its prominent ear tufts and yellow eyes. Its adaptability allows it to thrive in a vast range of environments, from dense forests to urban parks, where it preys on a wide variety of mammals and birds.
The Snowy Owl (Bubo scandiacus), also a member of Strigidae, is one of the largest species. It is identifiable by its nearly pure-white plumage, an adaptation for its Arctic tundra habitat. Unlike many relatives, the Snowy Owl is primarily diurnal, or active during the day, a necessity during the Arctic summer. Females tend to have more dark barring on their feathers than the mostly white males, which provides camouflage against the patchy snow and rock.
The Common Barn Owl (Tyto alba) represents the Tytonidae family and is found across six continents. Its pale underparts and distinctive heart-shaped face make it visually unique. The Barn Owl relies on its sensitive hearing, aided by its asymmetrically placed ears, allowing it to pinpoint small rodents hidden beneath vegetation or snow.
The Burrowing Owl (Athene cunicularia), a smaller member of Strigidae, presents an unusual lifestyle. This species has long, exposed legs and actively hunts during the day, preferring open landscapes like prairies and deserts. They rarely dig their own homes, instead utilizing abandoned underground burrows dug by mammals like prairie dogs, where they raise their young.