We were headed back to the city after another day on the Eastern Shore of Maryland. The road was pitch black, wet with the rain that had pushed through the Delmarva earlier in the day. Dark shapes of leafless oaks and looming pines, pierced by our headlights, quickly reverted to silent sentinels on this moonless night. We finally reached bare farm fields, but the visibility was only marginally better.
We were driving slowly on the narrow road when a ghostly figure swooped through the beams of light. It was gone as suddenly as it had appeared.
Barn owls (Tyto alba) are nocturnal, and our fleeting encounter was typical of the way we humans see them: ghostly images in the night sky.
The barn owl is the most widely distributed raptor in the world. It lives on every continent except Antarctica. The barn owl is present throughout the Western Hemisphere, living wherever open fields serve as habitat for its prey. Its permanent range extends from Canada’s southern border all the way to Argentina’s southern tip.
Barn owls have large, rounded wings that carry them silently in their nightly searches for food. Just 15 inches tall, the barn owl’s wing span stretches out to 3.5 feet.
Unlike other North American owls, the barn owl has a heart–shaped white face. Its undersides are pale with streaks and dots of black. On top, the bird is a messy mix of reddish-browns, black, silver, and tan. Its tail is short and squared off.
Females are larger than males and tend to be darker overall.
Strictly nocturnal, the barn owl leaves the nest or roost in search of small mammals in open fields. Field mice, voles and similar species make up the majority of the barn owl’s diet.
Typically, these owls fly low over fields, watching and listening for any movement that could indicate a meal. At times they seem to hover, and they can be seen with their long feathered legs hanging below them. Other times they hunt from a perch, always at the ready.
Although their night vision is excellent, barn owls primarily use their sense of hearing to locate prey. The facial disk and feather patterns funnel sounds to their ears.
Barn owls kill with great efficiency. After they snatch up prey, they quickly consume the whole thing.
The stubby, bone-colored bill is not designed for ripping flesh from bone. A few hours after eating its meal, the barn owl regurgitates a pellet of indigestible parts: bones, fur and small amounts of viscera. These pellets are regularly found near favorite roosting sites and below nests. In fact, they are a great clue when birders are looking for these elusive creatures. Pellets also provide scientists with a record of what the birds are eating.
Barn owls get their name from their frequent use of the rafters of barns for their nests. If grain is present, a plentiful supply of mice is probably available, too.
In addition to the presence of pellets, tell-tale white streaks just below nesting sites are also useful in helping birders and scientists locate these birds year-round. The white is from the bird’s waste, which it unceremoniously deposits while perched on the nest’s edge.
We had lived on a farm in Pennsylvania and a barn owl occupied the largely unused barn. Throughout most of the year, when the windows were open, we could hear the hissing shriek of the owl as it prowled the night sky. Months later, we discovered the bird’s nest, located in the hayloft. The white stain on the cross beams gave it away.
Barn owls usually mate for life. The female forms the nest out of her own regurgitated pellets. She pulls the pellets apart to form a shallow cup nest.
Clutch sizes vary widely with as few as two or as many as 18 eggs. Weather and availability of food dictate the frequency of breeding. Some pairs produce up to three broods in a year. Incubation takes about a month and the nestling period nearly two months more.
Although they can be prolific breeders, barn owls may be in decline. Population counts are exceedingly difficult because of the owl’s nocturnal habits and secretive roosts.
They certainly suffered from DDT poisoning and may be affected by poisons put out for rodents.
Habitat loss, as usual, is most likely the biggest contributor to the decline.
Barn owls are still widespread, but for most of us they exist as ghostly images, if we think of them at all. They are like those human night owls who clean our offices, mind our power plants and care for the sick.
They are out of sight and mind, but playing a vital role, either in the natural or human landscape. Learning more about them can be revealing and enriching, both of which they really deserve.