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One of the rituals that accompanies owning a dog is the morning "airing." That's code for letting the dog out to relieve itself after a long night of bladder control. For our new Labrador pup this usually happens sometime between 6:00 and 6:30 a.m. At this point in the winter, and at this pre-dawn hour, the sun has yet to color the eastern sky, or peek above the horizon; in terms of illumination, it's not quite night, but far from being day.

One recent morning as Bella and I were observing this ritual, I heard a chilling five-note call that could only be made by one creature: an owl. Bella's ears perked up, and I wondered for a moment if this unexpected, almost ominous sound, would make her think twice before venturing out on her cable.

Knowing how large some owls can be, I momentarily pondered the almost ridiculous possibility that she might be attacked. If she were still the tiny 12 pound pup we brought home in November, rather than the 35 pound pre-adolescent she is now, that might have been possible.

Though some owls hunt in broad daylight, most hunt either during the semi-dark hours of dusk and dawn, or in the very dark of the night. It is a niche reserved for them, unlike the other birds of prey, the hawks, eagles and ospreys, which hunt by day. As a consequence, we see far fewer owls than there may be living and hunting nearby.

Birders are very adept at identifying birds by their calls or songs; many of the owls can be identified that way. The sound that Bella and I heard was the characteristic tone sequence of the great horned owl. It is a far-carrying cadence, described phonetically as "Hoo ... hoo-hoo ... HOO ... HOO." The second and third notes are shorter than the rest, the last two notes loudly punctuate the tone phrase, like exclamation marks.

Folklore tells us that the hoots and other vocalizations of owls may serve the purpose of alarming prey into scurrying for cover, helping owls to locate them. I've always wondered if this could be so, given the fact that fear often causes a creature to freeze, rather than move, until it locates the source of danger. Alternative explanations are that these sounds help owls declare territories and locate mates. For the great horned owl, which begins nesting in January, before virtually any other northern bird, this mate location and territory-claiming explanation certainly makes sense.

Some birds have feather structures that create a distinctive noise when they fly, like the goldeneye duck, whose nickname "whistler" gives some idea of the sound its wings make in flight. Owl design is just the opposite. The leading edges of their wing primary feathers have stiff fringes, while the trailing edges of the primaries have soft fringes. This reduces wing noise and air turbulence. Soft feathers covering the owl's wing surfaces also reduce flight noise. The net result is greater stealth in an owl's aerial attack.

The great horned owl gets its name from twin tufts of erect feathers, one on each side of its head. These are believed to be only of display value, like the crests on songbirds like the cardinal and blue jay. "Great" is an apt description, for, at 24-25 inches in the body, and with a wingspan of 54-55 inches, it is the largest owl likely to be found in abundance year 'round in Minnesota. The great gray owl is often slightly larger, but only becomes common in occasional winters when a shortage of food causes it to move south out of Canada in search of prey. Such infrequent events are called "irruptions."

Although the hooting of a great horned owl has an eerie, foreboding quality about it, I would welcome any that chose to establish residency in the tall pines and spruces that border our lot in town. We have an over-abundance of rabbits, both summer and winter; only great gardener diligence can keep from doing harm to plants and shrubs. Great horned owls count rabbits high in their dietary preferences, which also include mice, squirrels, birds as large as grouse, reptiles, frogs, lizards, and even insects.

Owls generally swallow small prey animals whole, and down their larger prey in chunks, fur, feathers, bones and all. They later regurgitate the indigestible parts as oval pellets, something that has made the study of their eating habits a more or less open book for scientists.

Like wolves, bats, and certain other creatures, owls have a stereotype among humans; twin stereotypes, as a matter of fact. Owls, along with witches, bats and black cats, are members of the mysterious Halloween cast of characters. Yet "Owl" is also the wise mentor and teacher in the Winnie the Pooh children's tale, and owls are reliable, valued messengers between the worlds of wizards and humans in the Harry Potter book series.

Maybe the owl's mixed reputation can be best explained as human cultural baggage, part of our yet-to-be-extinguished fear of the unseen and the unexplained things of nighttime darkness. From the biologist's point of view, however, owls are a standout example of creatures that are admirably adapted to their environment. For most owl species, that means adapted not only to their physical environment, but to the mysterious environment beyond the sunset.[[In-content Ad]]

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