Ghouls and goblins are figments of the imagination, but a very real flying creature can swoop from the air to flog or frighten us at any time of the day or night. Of all the Halloween “boo birds,” the owl is one most deserving of its reputation for spooky powers.
Myths, legends and literature give the owl otherworldly traits. Ancient Romans connected the owl to Minerva, the goddess of wisdom. The philosopher Georg Wilhelm Friedrich Hegel alluded to Minerva’s owl in an often quoted line from his essay “Philosophy of Right”: “The owl of Minerva takes its flight only when the shades of night are gathering.”
In other words, owls and wisdom come to us when we are in peril or near death.
Recent children’s literature casts owls as knowing, benevolent creatures. Think of Winnie the Pooh and the Harry Potter series.
It must be the size of their eyes that makes them wise, because in mass an owl’s eyes are larger than its brain. The eyes of an owl are large, making up as much as 5 percent of its total body weight. The eye of the snowy owl is almost as large as a human’s eye.
But owls do not have the largest eyes in the bird kingdom. That distinction belongs to the ostrich.
Owl eyes are set widely apart on a facial disc that acts as a sensory plate somewhat like a TV satellite dish. The eye of the owl cannot move in its socket, but owls have great peripheral vision: The 13 vertebrae in their necks (humans have only seven) allow the entire head of the owl to turn almost 270 degrees.
And an owl can swivel its head so quickly that some observers have mistakenly reported that owls can turn their heads in a complete circle.
Owls also have binocular vision. Both eyes see an object at the same time, but the view from each eye is slightly different. Since the eyes of the owl are spread apart on a broad face, their binocular vision enables them to perceive depth with great precision.
And of course, owls can see at night. Compared to the eyes of daytime hunters like eagles and hawks, the large lens of the owl’s eye allows more light to strike the retina. They gather more light in dim conditions and so can see prey more easily. Great horned owls are masters of Arkansas’ nighttime skies just as red-tailed hawks are the dominant species of those skies in the day.
But owls can see in the daytime, too, and they are not blinded by light.
One ornithologist reported that as good as owl vision is at night, it is even more acute in daytime. An owl that was picketed out in a field during daylight hours was able to detect a hawk flying high above that at first was unseen by researchers.
THE PRICKING OF THEIR EARS
Even when they can’t see, owls can track prey by sound. Some have been seen swooping down to take a vole as it moves below a thick blanket of snow or leaves.
Scientists studying the hearing of barn owls got the ideas that led to the discovery and development of sonar. Research into owl hearing was considered top secret in World War II, and that research ultimately contributed to the Allies’ success in submarine battles.
It’s not merely that they have good receptors. The ears of owls are asymmetrical, with each ear canal different. These features give them a broader frequency range of hearing than other birds. Owls have a cochlear response to sound that is 10 times faster than human hearing. In front of their ears on each side, and beneath their feathered facial disc, a movable skinfold collects and concentrates soundwaves coming from behind.
SILENT ATTACK
Their feathers allow them to glide noiselessly.
When most birds fly, air rushes over the surface of the wings, creating turbulence and a gushing noise. Among most owls, fluted comb-like edges on the feathers break down the turbulence into thousands of micro-disturbances. This effectively muffles the sound. Owl flight is so quiet that it does not interfere even with the owl’s keen sense of hearing, and that allows the bird to make slight adjustments on the wing just before it strikes its prey.
OWLS IN ARKANSAS
Worldwide there are more than 200 species of owls, divided into two families: 189 species of “true owls” and 16 kinds of “barn owls.”
Barn owls have a heartshaped facial disc; true owls have a circle of feathers around each eye.
Twenty species of owls live in North America. The Natural State hosts nine species of owls. Four kinds live here year-round and can be seen or heard regularly. One species, the short-eared owl, is in Arkansas only in the winter. Another four kinds of owls are seen only occasionally.
Barn owls get their moniker from the fact that they frequently roost and lay eggs in abandoned farm buildings. They also roost on cliffs and in trees, but they do not build nests, preferring to lay their eggs on a flat shelf of wood or earth.
Barn owls may well rank among the most effective hunters on the planet. Farmers who are fortunate enough to host one in their barn will see a dramatic reduction in the number of rodents.
Viewed from below when they are in flight, barn owls are a ghostly white and move with an eerie side-to-side motion. Their backs are a mottled dull orange and grey; their eyes are dark.
Though barn owls are widely spread across North America, their numbers are in decline due to reduction of habitat and inadequate nesting sites. They are not frequently seen, but if you know where they roost, you can usually find them there during the day.
Barred owls (when said quickly, it sounds confusingly like “barn owls”) are so named because of the dark bars on their abdomens. They are more frequently spotted than the other species of Arkansas owls, mostly because they venture out to hunt in the late afternoon and midmorning. Other owls are more strictly nocturnal.
On cloudy and foggy days, they can be seen perched on tree limbs. During the bright part of the day, barred owls are frequently harassed by small songbirds and crows. An owl can sometimes be found by following the ruckus made by the other birds.
Barred owls are more vocal during the day than other owls, and their call is a loud squawk: “Who cooks for you? Who cooks for you-all?”
The smallest owl in Arkansas is the Eastern Screech Owl, only 8 inches long with a 20-inch wingspan.
Its most common call is not a screech but a soft, mournful whinny. It is seldom seen because it is so small, strictly nocturnal and remarkably well camouflaged. Screech owls may be two colors, either grey or reddish-brown.
They have been known to strike unsuspecting humans on the head as they walk in the night. Such behavior is usually in defense of a nest, which is frequently in abandoned woodpecker holes. These diminutive owls eat mice and large insects, and may become prey for other larger owls.
The great horned owl is Arkansas’ largest owl, 22 inches long with a wing span of almost 5 feet.
It has large yellow eyes and a curved black beak. The protrusions atop its head are not horns but tufts of feathers that aid in hearing. Great horned owls do not build nests but instead take over the nests of other creatures, such as squirrels and eagles.
Strong talons allow this owl to grab skunks, rabbits and squirrels as its prey.
Short-eared owls are seen in Arkansas only in winter. They live and hunt in open fields, roosting on the ground. They may be seen at twilight flying slowly and low over fields, searching for small rodents.
OCCASIONAL OWLS
The four species spotted only occasionally here include the snowy owl, the saw-whet owl, the burrowing owl and the long-eared owl. When any of these are reported, it causes quite a stir among birders.
Dan Scheiman, ornithologist for Audubon Arkansas, has a hunch that saw-whet owls may be in Arkansas in greater numbers than previously believed.
“The saw-whets do not answer recordings of their songs played at night like other species of owls,” he explains. “They fly toward the playbacks instead of answering and may not be seen in the dark.”
Bob Sargent, a bird bander in Alabama, has found “sawwhets galore” using mist nets at night in an area where they were not known to exist (his own backyard). Scheiman thinks that might be a way to test his hunch here.
INTO THE NIGHT
Park interpreters at many Arkansas State Parks regularly conduct “owl prowls.” A naturalist leads a small group into the woods at night, where they imitate the sound of an owl or play a recording to coax owls into answering back or flying near to investigate.
It is not unusual to get good looks at owls this way. Even a novice’s vocal imitation of the barred owl can draw a response.
Late one night as I was writing this story in my studio, I heard great horned owls “hoo-hoo-hoo” in the trees around the lake behind my house. I slipped outside to listen. The hooting was coming from three different directions - presumably from three different birds. I then conducted an owl prowl of my own.
I stood just under the eave of the carport. Placing my lower teeth on my upper lip, I sucked in gently, creating a squeaking sound. This way of imitating the sound of an injured mouse, I had been told, could conjure up an owl. Sure enough, shortly afterward, a great horned owl landed on a dead limb of the pecan tree by my bedroom window. I saw its silhouette against the moonlit sky.
Jerry Butler is a regular contributor to the Arkansas Democrat Gazette on topics related to birds. He welcomes stories and comments about birds at [email protected]
ActiveStyle, Pages 27 on 10/28/2013