By Debra Firmani

The owl's many mysterious calls, glowing eyes, unusual shape, and stealthy flight ability can be both fascinating and spooky, but at the bottom of these intriguing trademarks is effective evolution. With a fossil record 66 million years long, owls are one of the oldest groups of living birds. Scientists think some owls even descended from small dinosaurs, but no matter who their ancestors were, time has served these birds well. Nearly every aspect of an owl's current form contributes to his ability to capture prey.

The owl's large, reflective eyes are huge in proportion to its body, and produce the best night vision of any animal. The soft feathers surrounding the eyes funnel sounds into highly sensitive ears, enabling an owl to hear prey hidden beneath snow or even underground. A great gray owl can hear a beetle running through grass a 100 feet away or a mouse squeaking at a distance of half a mile.

While most birds have around seven neck vertebrae, an owl has 14, allowing him to turn his head 180 degrees to the right or left to track sound quickly. The softness and structure of owl feathers muffle the noise of flight so owls can approach prey without being detected. Once prey is spotted, the animal is securely grasped in an owl's powerful talons and carried easily back to the roost with the help of strong, broad wings that are large in relation to the owl's body.

Where to Look for Owls

Owls can be found on every continent except Antarctica and in nearly all types of habitat, but their solitary and nocturnal habits, as well as the effectiveness of their camouflage, often make them difficult to spot. Twenty-one of the more than 140 known species of owls live in North America. Though most owls prefer to stay far away from humans, barn owls and screech owls often live near human settlements because rats and mice are plentiful wherever people live.

Owls choose roosting spots that are well-hidden and protected from the weather. Territories vary with the size of the species, the number of offspring typically produced, and the area's food supply. A great horned owl may need a territory of up to 1,000 acres, while a great gray owl may need only a few hundred square feet.

A telltale sign that owls are living nearby is the pellet, a by-product of owl digestion. Owls eat their prey whole. They have difficulty digesting hair, feathers, and bones, so they compact these unusable materials into a pellet, which they then spit out. The type of pellet varies with the type of owl, and to a trained observer, a pellet can reveal not only the owl's species but also what the bird ate.

The Sound and the Fury

The word owl comes from the Old English word "ule," which means "to howl," and the bird's large and freely used vocabulary makes this a particularly fitting name. Patterns of short and long hoots enable owls to locate and communicate with one another. Some species of owls rarely make sounds, while others are constantly vocal. Calls heard in autumn are probably from males establishing hunting territories; calls heard in late winter or early spring are likely to come from courting pairs. The males' voices tend to be lower and to carry farther than those of the females.

Mated owls can stay together a long time, and may use the same nest for more than 20 years. They frequently settle in holes in trees or the abandoned nests of other birds instead of creating nests of their own, but they are extremely devoted to their offspring. The female does most of the incubating while the male supplies food and fiercely protects the nest against intruders of any size. Attacks upon intruders become more aggressive once the owlets have hatched, and both parents defend and teach the owlets until they are independent.

Owling

Learning to recognize different owl calls will help you find and identify owls in your area. A good way to get started is to go into the field with an experienced owler. Most woodland owls call at dawn and dusk, so set out two or three hours before sunrise or two hours after sunset.

• Sound. If you play pre-recorded owl calls to elicit responses from owls in the vicinity, do so sparingly—and never during mating season. Indiscriminate use of recorded owl calls has been known to bring the breeding cycle of some owls to a halt. A better way to draw owls into the open is to emit hisses, cheeps, and squeals suggestive of a prey animal in distress.
• Light. Photographers' flashguns can damage an owl's sensitive eyes and diminish his ability to hunt. Use them moderately, if at all. While a flashlight will allow you to see owls at key moments, use light sparingly so you retain your night vision and have little impact on the owls. Let common sense and caution be your guide. If you think an owl-finding strategy might have a harmful effect, don't use it.

How You Can Help Owls

Although crows and squirrels eat owlets if they can, the principal killers of adult owls are human beings. Many owls found dead have been shot, trapped, hit by cars, or electrocuted on power lines. Humans also alter owl habitats, and the effect of insecticides on the food chain threatens owl survival. The most common cause of owl death, and the main threat to owlets, is starvation. Up to 50% of owlets fail to survive the period when they learn to hunt for food.

We can help owls by preserving their natural habitats and using organic methods rather than chemicals to eliminate agricultural pests. We must offer them a healthy ecosystem and a safe food supply. Preserve old, hollow trees and build owl nesting boxes in protected places. With our assistance, these important and impressive creatures will continue to live among us for millennia to come, protecting our crops, serving as symbols of wisdom, and filling us with wonder.

Debra Firmani is the former editor of The HSUS's Wild Neighbors News.