Almost everyone is familiar with the classic image of a Barn Owl. The heart-shaped face with the large round eyes, the tawny body, and the adorable “smiling” expression they make when they sleep. But how much do we really know about these animals? Despite their secretive nature, biologists have been able to learn a lot about them. In recent years, their populations in Ohio have been declining, to the point where they are classified as “endangered” by the state. By educating people about these beautiful birds, enough people can hopefully take an interest in their welfare to push for measures that will allow them to flourish once again in the Buckeye State.
The scientific name for Barn Owls is Tyto alba. Tyto means “owl” in Greek and alba is Latin for “white.” They are the most widespread of any owl, found in almost every area of the world with the exception of desert and polar regions. This dramatic spread has resulted in up to 46 identified “races” of Barn Owl. The largest is the North American form, which is almost double the size of some of the smallest forms found on the Galapagos Islands. They are found in a variety of habitats, including grasslands, deserts, marshes, agricultural fields, strips of forest, woodlots, ranchlands, brushy fields, and even suburbs and cities. They require large areas of land over which to forage, or hunt, but they prefer to nest in cavities such as hollows of trees or abandoned buildings. Barn Owls have been also been found nesting in church steeples and in Yankee Stadium.
Even though their scientific names refer to them as being “white,” this is not completely true. Barn Owls have a mix of grey and buff colors on their backs, with white bellies and underwing areas. Most are between 13 and 15 inches in length, with wingspans ranging 31 to 37 inches. Female Barn Owls have slightly more red color than males, and have more dark spots on their chests. A study of these spots revealed that females with more of them had fewer parasitic fleas and were more resistant to diseases. This led scientists to suggest that males select female mates based on the number of spots that they had, to ensure a healthier mate and thus healthier babies.
Barn Owls do not live for very long in the wild; their average lifespan is 4 years. However, in captivity, they may live much longer. The oldest Barn Owl ever recorded was a captive owl in Britain, who retired from breeding at the age of 25. And what’s more, the oldest known Barn Owl in the United States lived in Ohio! It died at the age of 15 years and 5 months.
Barn Owls have excellent low-light vision, but their best sense by far is their hearing. Owls in laboratory settings have succeeded in catching prey in complete darkness. Their ears are asymmetrically placed on either side of their head, which actually aids in catching prey; the owl’s right ear is more sensitive to sounds above them and their left ear is more sensitive to sounds below them. This difference allows for the owl to more accurately determine the angle and elevation of whatever they are hearing. Barn owls also are able to very quickly orient their faces towards the source of a sound. It is thought that this allows them to achieve the maximum accuracy in locating their prey, both visually and hearing-wise. One study calculated that their average error in locating prey was 2 degrees out of a 360 degree range, which is more accurate than any known animal.
Because they relatively high metabolism rates, Barn Owls consume a very large amount of prey. Scientists have estimated that they eat more rodents (their primary food source) than any other animal. In the US, they primarily eat voles and shrews. They also eat bats, rabbits, and sometimes birds (starlings, blackbirds, and meadowlarks). They don’t have many natural predators, but opossums, raccoons, and large raptors have been known to prey upon Barn Owls.
Barn Owls have a number of adaptations that allow them to be particularly effective hunters. They are able to fly almost completely silently due to tiny serrations on the front edges of certain wings, as well as fringes that trail to the backs of their wings. These help break up the airflow over the wings, decreasing turbulence and any sounds that would accompany it. Also, they have an extremely forceful striking motion when leaping upon prey – they can deliver up to 150 times the force of a mouse’s body weight when killing. However, they don’t use this force to actually kill their prey, but to penetrate thick snow or leaf litter so as to grasp prey more effectively.
All in the Family
Barn Owls are very prolific breeders. Their breeding season is in March through June. They are socially monogamous, meaning that they mate with only one other partner. About a month before the female starts laying eggs, the male will begin bringing her food, and will leave the rest in a hidden place (called a “cache.”) Once she has reached a peak weight, the male will ritually present some food and mating will occur. Eggs are incubated for about thirty day, and because hatching takes place over a prolonged period, chicks can have several weeks of difference in age.
Chicks develop very rapidly in the nest (which is made out of sculpted pellets regurgitated by the female). After a week they can move around; at two weeks, they are half of their adult weight. After three, their feathers start to grow in and they can eat whole food (as opposed to having it torn up for them by their mother). At four weeks, males stop bringing food to the nest and females start occasionally leaving the nest to roost elsewhere. They are still dependent upon their parents until about 13 weeks of age, during which time their mother teaches them to hunt on their own; afterwards they begin to leave the nest on their own.
While in the nest, hatchlings often compete for food which is distributed to them by their mother after the father brings it to the nest. Some studies have suggested that this competition has resulted in distinct songs between siblings, as a way of distinguishing themselves to their mother.
Barn Owls, like humans, sometimes go through breakups! Even though they are socially monogamous, they may experience what biologists call “divorce.” There are several possible reasons for why this happens. Current research suggests that it occurs after breeding seasons where the owl pair was not reproductively successful, and that it is a mutual choice by both owls to find more compatible partners. This implies that divorce is actually beneficial for both parties, and evolutionary adaptive.
How You Can Help
Barn Owls are not considered endangered on a global scale. However, they have been categorized as endangered in several Midwestern states, including Ohio. The main factor contributing to their deaths is thought to be habitat loss; however, in some areas this problem can be solved simply by installing appropriately-sized bird boxes for the owls to nest and roost in. Other factors contributing to their deaths are collisions with cars, as they fly very low when they are hunting and they are difficult for drivers to see. They have also been very heavily affected by pesticides and rat poisons in the past. Thankfully, many farmers have realized that Barn Owls can actually be of use in eliminating pests, and have stopped putting out poisons in favor of allowing the owls to naturally maintain the rodent population.
In the past, farmers have seen Barn Owls as omens of evil. Of course, this isn’t true – Barn Owls are fascinating animals that deserve our respect and, especially in Ohio, need our help! With a bit of effort and appreciation, Barn Owls can continue to live peacefully alongside humanity and the rest of the natural world. – Samantha West
Samantha is a senior Zoology major at Ohio Wesleyan University. She has loved animals and wildlife since childhood, and hopes to work in species conservation upon graduation.