Many owls have tufts of feathers on the tops of their heads which are often
referred to as "horns" or "ears." Even their names reflect this
terminology: Great Horned Owl, Long-eared Owl, and
But these structures are neither horns (a bony
outgrowth of the skull of some mammals), nor are they ears or in any way
associated with hearing. A bird's ears are on the side of the head not on the top where these feather
tufts are located.
So what purpose do these "horns" or "ears" serve?
It is thought that these structures may play a role in non-vocal
communication. Nearly all of the owls with these "horns" or "ears" atop the head are found in dense woodlands.
Owls of open country often have rounded heads. The Short-eared Owl is a bird
of open lands and, while it does have these feather tufts, they are seldom
visible unless fully erected and even then, they are quite short. An owl
silhouetted in open country may be relatively easy to see while a bird in
dense woodlands may be much more difficult to locate. By erecting these
tufts of feathers, a more distinct outline suddenly becomes visible. This
may allow pairs of birds (or families with young) to silently keep track of
each other's presence, communicating by erecting and lowering these
feathers. These tufts may also serve as signals to potential enemies by
making the owl suddenly seem larger and more of a threat when the feathers
become fully erect atop the head.
In addition to communication, "ear" tufts play a very different role in
assisting the owl, a role which is opposite of communicating. They assist in
camouflaging the bird. Erecting the feathers as a way to communicate
is done while the bird is in the open, on a perch where it can be easily
seen. While sleeping or trying to avoid being seen, many owls
(especially Screech-Owls) close the eyes tightly and erect the feathers over
the brow and top of the face in such a way as to form a "V". Erecting the
ear tufts fully extends this V above the head and breaks up the visible
contour of the face. In these cases, the owl is usually perched on a branch
and is pressed up against the tree trunk, or more frequently, perched in a
tree hole. The pattern of coloration in the feathers, combined with the
concealment posture, makes it nearly impossible to distinguish the owl from
the bark of the tree trunk.