Barn owls are cavity nesting birds of prey but they do not create their own nest holes. Instead, they frequently use cavities from other birds or hollow trees, and they readily move into nest boxes. With the right nest box, it is possible to encourage barn owls to become permanent residents.
Encouraging Barn Owls to Nest
Many farmers encourage barn owls to nest because they are efficient hunters that prey almost exclusively on small rodents such as mice, voles and gophers. With hungry barn owls in the area, less money will be needed for rodent control and because they are nocturnal birds, barn owls rarely bother livestock or pets.
Despite the fact that barn owls are one of the most widespread owl species, they can be finicky about where they nest. Open areas are best, including grasslands, marshes and fields. Some sparse woodlands are acceptable, but barn owls generally avoid very dense forests that are a preferred habitat of great horned owls, one of their natural predators.
To encourage barn owls to nest in appropriate areas, avoid using chemicals to kill rodent populations. Concentrated poisons in the rodents can be harmful to owls, and barn owls will not nest if there is insufficient food. Place a barn owl nest box at least 15-20 feet high, but be sure the opening is shaded from the sun and wind. If the box is mounted on a pole, use a baffle to prevent cats, raccoons and other predators from reaching it. Nesting platforms can also be placed in barns or silos if the owls will be able to access them easily.
About Barn Owl Nest Boxes
If the boxes are in the right habitat with sufficient prey available, barn owls can be encouraged to nest in a range of box styles. A typical barn owl nest box has a six-inch entrance hole that is suitable for a barn owl but too small for a great horned owl, and the hole should be approximately four inches above the floor of the box. No perch is necessary, and adding one may give footing to predators.
Drainage holes are essential for any safe birdhouse, including owl boxes. Some box designs include a narrow slat along one edge so adult birds can kick out unwanted debris. To further facilitate cleaning, the box should have a side or top that can be opened.
The interior dimensions of barn owl nest boxes can vary greatly. One brood of barn owls may have 2-18 nestlings, and as the owlets grow a smaller box can become crowded very quickly. In general, an owl box should have a floor no smaller than 10x18 inches, though larger boxes are common and just as likely to be attractive to nesting owls.
Where to Buy Barn Owl Nest Boxes
Several retailers offer specialized barn owl boxes, either as kits or prebuilt boxes. Prices range from $30 to $500 or higher depending on the size and design of the box, and many retailers offer bulk discounts for purchasing multiple barn owl boxes.
Many of the same retailers also offer barn owl nest box plans for birders who would like to construct their own boxes.
Nest Box Tips
When barn owls move into your nest box…
- Do not disturb nesting owls. Barn owls are protected by state and federal laws and moving, destroying or disrupting a nest is a serious crime.
- Wear earplugs. Barn owls are noisy and young owls may beg for food all night long with loud screeches and other cries. Avoid positioning a nest box near a home or window if these nocturnal noises will disturb you.
- Clean the box in late fall. Barn owls will regurgitate pellets in the nest box to serve as cushioning for the young birds, but this material can be removed after the nesting season ends. Cleaning the box will make it more inviting for successive owl pairs.
Observing nesting barn owls can be a rewarding and exciting experience, and choosing the right barn owl nest box and positioning it appropriately will encourage these ghost owls to become permanent residents on your property.