Photo by Sarah Geiger.
The Barn Owl—Ghost of the Night
A barn owl is one of the most easily identified owls. The peculiar look of its face separates it from the eight other species of owls occurring in Illinois. The large whitish, heart-shaped face has a monkeylike, almost comical look. No ear tufts are present. Body plumage is light colored, ranging from whitish, to light tan and buff, to shades of cinnamon. Females are showier than males with a more heavily spotted chest and a greater reddish tint to plumage. Stripe or bar markings are lacking on barn owls. Very long legs are another trait.
In addition to natural cavities, this once-endangered barn owl nests in farm buildings such as barns, cribs, and silos as well as commercial grain elevators. During the early 20th century, these elevators were more accessible to barn owls, being made of corrugated metal sheeting and wood with more places where barn owls could enter. These early-day elevators were a far cry from the modern-day monoliths of concrete and steel. As a result, barn owls occasionally found these elevators a place to nest even though regular human activity was ever present in these townlike settings, usually along railroads.
Before European settlement, cavities in cliffs and rocky outcrops and large hollow trees sufficed as barn owl nest sites. Today in southern Illinois, where you are most likely to see barn owls, old hollow bald cypresses are still a favorite.
Four or more roundish white eggs are laid in a natural cavity or nest box. The nest lacks any amenities aside from owl pellets. Late spring to early summer is the peak nesting, incubation, and brood-rearing time. Barn owls will nest two or more times throughout the year if prey are abundant.
Young barn owls may sometimes fall out of a nest. Aside from placing them back in the nest, just leave them alone. Their best chance for survival rests under the care of their parents. Owls tend to be exceptional parents. Great-horned owl parents successfully raise a young owlet on the ground that has fallen out of the nest, even during cold, snowy weather in late winter.
The barn owl’s most favorite nesting locations are often near grassy habitats that harbor mice, voles and small birds. Prey are hunted only at night, even though this owl sees very well in daylight. Prey are located by sight and sound. These owls can see exceptionally well in low light conditions, but their ears are even better than eyes, enabling them to locate prey in complete darkness. A barn owl’s hearing is the best of any animal tested to date. Its ear canals are offset in two dimensions. One ear canal is set higher on the head than the other, and one is more forward. This arrangement enables a barn owl to get a three-dimensional fix on a prey’s sound and zero in for the kill.
Barn owls hunt at night by flying low—back and forth—over open habitat, searching for small rodents primarily by sound. Experiencing this nighttime, mothlike flight of this light-colored owl has been described as seeing a ghost. Sometimes, these flights end tragically when a barn owl crosses a rural road and is hit by a vehicle.
Barn owls can swallow smaller prey whole—skin, bones, and all. They form and cough up pellets instead of passing ingested material completely through the gastrointestinal tract. Some prey are probably dismembered because parts of prey are found at nest sites. Pellets are collected and studied by researchers to determine what has been eaten.
Barn owls have big appetites, hence their reputations as being exceptional at mouse control in barns, cribs, and elevators. It is not uncommon to find evidence of a barn owl consuming a hundred or more mice by examining pellets. Researchers examining one barn owl’s leavings from a Michigan barn found remains of 189 mice and 1 short-tailed shrew.
Since the 1960s, the barn owl’s decline is connected in part to the decrease of pastures, hayfields, and other grasslands, and also to the bioaccumulation of DDT that caused eggshell thinning. Additionally, other pesticides used to control rodents in and around farm buildings may share some of the blame. However, according to breeding bird surveys, since the mid-1990s, populations may be rebounding somewhat.
The Illinois Natural History Survey conducted a recent study on barn owls in southern Illinois that was published in 2014. The study determined the success of placing barn owl nest boxes in various locations and situations. Some were placed in barns and other structures. Others were placed on poles in various habitats. Although most boxes were not occupied, some were used. A number of factors were associated with nest box occupancy, including crops and grassland cover in the surrounding landscape.
How can you help?
Construct nest boxes and place them near existing grassy habitats—the closer the better. Barn owls do most of their hunting within a mile of their nests—in hayfields, pastures, CRP acreages, orchards, and vineyards. In the south, orchardists are strategically placing nest boxes in orchards to encourage barn owl control of rats and other pests.
Why not plant substantial grasslands to attract the rarest of Illinois’ owls, as well as other wildlife? And construct and put up nest boxes in areas of the state, such as northern Illinois, where barn owls are very uncommon. You may never know. You might get the surprise of a lifetime! For barn owl nest box plans and hints for placing them, see “Help Bring Back the Barn Owl!” by the Illinois Endangered Species Protection Board and Illinois Department of Natural Resources.
Robert J. Reber is an emeritus faculty member in the Department of Food Science and Human Nutrition of the University of Illinois at Urbana-Champaign. He has been a lifelong student of many aspects of the Natural World, including archaeology. Reber has served as a managing editor and author for publications such as The Illinois Steward and the Illinois Master Naturalist Curriculum Guide.
A special thanks to Mike Ward, an ornithologist at the Illinois Natural History Survey, for reviewing this article.