"THE OWL, NIGHT'S HERALD" Shakespeare.

©By Susan B. Eirich, Ph.D.

It is a winter evening on South Leigh Creek, a cold, still night. From deep in the cottonwoods a soft, low-pitched  “whooo-ooo-whooo-ooo floats mysteriously on the air. Silence. Then from another direction an echo…“whooo-ooo-whooo-ooo. The first sound is repeated. Silence. The night forest is still. A sensation that something has just flown low overhead, but such a silent presence you think it must be your imagination. The Great Gray Ghost, the Phantom of the North, the great gray owl, Strix nebulosa, is hunting.

He was letting other owls know of his presence. They were responding. There are others here. Many others. Our South Leigh Creek wildlife corridor, right in our valley, has the greatest wintering concentration of great gray owls in the lower 48 states. They tend to congregate where there is an ideal combination of forested places to roost, hide, and nest; places that also border open fields where there are mice and voles. This huge magnificent bird, the largest owl in North America with a wing span of up to five feet, lives on the tiny mice and voles they find in those fields. They can live up to 40 years in captivity, but their lives are shorter in the wild. Their greatest source of mortality is starvation when they can’t find enough rodents. Though it is vital that we protect our wildlife corridors, we must also preserve the open fields adjacent to them, keep them free of lawns, of free-ranging and feral cats. Another thing they must have are nesting sites. They do not build their own, but raise their young in abandoned stick nests made by hawks or ravens, or in the hollow tops of large broken off rotten tree tops that from our perspective would appear useless. They may use the same nest for several years.

These silent hunters are superbly adapted. Their hearing is so acute they can hunt by sound alone, locating mice more than one foot under the snow in the dark, plunging with pinpoint accuracy into the snow talons first, to grasp their meal. Their face feathers act like a “radar dish,” funneling sound into their ears. The owls sit silently, listening for the sound of movements through ground cover or snow.  They have “binocular” hearing in which there is a tiny difference between the time the sound reaches one ear, then the other. The owl turns its head so that the sound arrives at both ears simultaneously – then it knows its prey is right in front of it. They can tell a left-right time difference of about 0.00003 seconds (30 millionths of a second). They also have extraordinary night vision. Native peoples explained their vision by believing owls had a magical inner light.  

With a normal bird in flight, air rushes over the surface of the wing creating turbulence, which makes a gushing noise. An owl’s wing has a comb-like feathered edge that breaks down the turbulence into little groups call micro-turbulences. This muffles the sound of the air rushing over the wing, allowing the owl to fly silently, and use its superb hearing to locate prey. Their wings are large, rounded and broad making it possible to fly buoyantly and effortlessly without much flapping; and glide easily and slowly for long periods of time.

The great birds are at the southernmost end of their range here, connected up the to the vast regions of Yellowstone and north up the spine of the Rockies through the South Leigh wilderness corridor. Owls have been with us, a source of awe and fascination, since the dawn of human consciousness. One of the earliest human drawings dating back to the early Paleolithic period was a family of owls painted on a cave wall in France. In many cultures they are believed to hold the newly released soul of loved ones who have recently died. Those peoples hold that we must not harm them or we will be harming a human spirit. The belief may not be scientific, but it has a wisdom ….it  helps preserve a species that is both wondrous, and beneficial to humans. We don’t have such beliefs. But may we be rational and wise and strong enough to keep them with us here in our valley. 

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