Amazing Owl Ears

Owls are nature’s stealth aircraft—they can fly more quietly than most any bird. Their wing feathers allow their wings to beat and glide through the air so silently that they can swoop down unawares and grab rodents and rabbits for their meals. The leading edges of an owl’s wings are serrated, which reduces eddies of air shed by the wing, and thus the noise.

An owl’s eyes are also amazing organs. They are very large—an owl’s stare from a photograph can be disturbingly intimidating. Their eyes are placed in front of their head—rather than at the sides, as for most birds. This gives an owl stereoscopic vision—excellent depth perception—so it can accurately pounce on its pray. Furthermore, owls use their eyes in the dark.

But an owl’s ears are probably their most incredible sensory organ. The eye of an eagle may be able to pick out dinner morsels a mile or so away, but the ear of the owl is equally impressive. Their large heads and fan-shaped feathers efficiently direct sound to their ear openings—and those openings are asymmetrical on the head. One is slightly higher than the other, which increases their ability to zero in on the location of animal sounds.

But the champion hearer of all is also the largest owl of all: the great gray owl. This bird lives in the far north; in central Canada and up into Alaska. It may be the largest owl in the Americas, but the smaller great horned owl is 50% heavier. Why? In order to keep warm in its frigid environment, the great gray owl puffs up its feathers, insulating its body.

And those ears of the great gray! It can sit on the branch of a tree and hear the sounds of a vole several hundred feet away, under several feet of snow! Think about what that implies about the acuteness of the hearing mechanism of this bird. Snow is a good thermal insulator and a good sound absorber. It does an excellent job of muffling the sounds of a skittering vole—who is comfy and believes itself safe, hidden under a deep snow bank. And what overly confident vole would think that an owl perched a football-field distance away could ever be a threat? There goes another meal for the great gray.

That extraordinary hearing capability of this owl implies yet another remarkable fact: the environment must be exceptionally quiet in that far frozen north. Even the slightest background noise—a gentle breeze wafting or any sound from another animal—would prevent the owl from picking out that buried vole. That silence is precious to the owl. It never gets that quiet in the States. The great gray owl had better remain in its isolated north country.