Owls do not have true horns. The structures often mistaken for horns are specialized feather groupings that project from the top of the head, creating a distinctive, pointed appearance. This visual feature is a source of frequent misunderstanding about the bird’s anatomy.
Anatomy and Terminology of Ear Tufts
The appendages on an owl’s head are not made of bone, cartilage, or the keratinous material found in mammal horns. They are composed entirely of dense, elongated feathers that an owl can raise or lower using small muscles. The scientific term for these structures is “plumicorns,” derived from the Latin words pluma for feather and cornu for horn.
Plumicorns are frequently, but incorrectly, called “ear tufts.” This term is misleading because they have no function in the owl’s hearing. The bird’s actual ear openings are located on the sides of the head, hidden behind the facial disc feathers.
The True Purpose of Plumicorns
The primary roles of plumicorns relate to behavioral ecology, specifically camouflage and communication within their species. When an owl is roosting during the day, raising the plumicorns helps to break up the smooth, rounded outline of its head. This disrupts the bird’s silhouette, making the owl appear more like a broken tree branch or a piece of bark against the trunk.
This camouflage posture is a defense mechanism against predators, making the owl nearly invisible in its environment. Plumicorns are also actively used in non-vocal communication with other owls. By adjusting the position of the tufts—pointing them straight up, flattening them, or angling them—the owl signals its emotional state.
A fully erect display can signal heightened alertness, aggression, or a territorial warning to rivals. Conversely, if the owl is trying to appear non-threatening or submissive during courtship, the plumicorns may be held lower.
Distribution Across Owl Species
Plumicorns are not a universal feature across the more than 200 species of owls worldwide. Only about 50 species possess these characteristic feather tufts. The presence of tufts is strongly correlated with the owl’s primary habitat, often found on species that live in forested or heavily wooded environments.
Classic examples of owls with prominent tufts include the Great Horned Owl, the Long-eared Owl, and various Screech Owl species. These birds frequently roost in trees where the camouflage provided by the plumicorns is most effective. Species that inhabit open grasslands or fields, or those more active during the day, tend to have rounder heads without these feather projections.
Common species that lack plumicorns include the Barn Owl, the Barred Owl, the Snowy Owl, and the Tawny Owl. The existence of plumicorns can be an indicator of an owl species’ typical environment, suggesting a need for visual disruption while perching.