Owl Boxes: Nature’s Pest Control

Late winter may seem like an odd time to talk about nesting season, but it is the ideal time for the most underrated and helpful nesting birds: owls. These raptors begin nesting in late winter, and with the right owl box and an owl-friendly habitat, you can easily invite them to take up residence on your property. Why would you want to? Because owls are spectacular help for farmers, gardeners, and homeowners as they provide superior pest control without toxic chemicals.

Why You Definitely Want An Owl Nesting In Your Back Yard

Owls are not usually the first birds that come to mind when you think about attracting birds to your yard. Generally nocturnal, owls are rarely seen, and they do not typically visit the feeders or baths associated with backyard birds.

Mice, rats, gophers, voles, and shrews are some of the most common pests that damage crops and buildings. They eat livestock feed, contaminate stored seed, transmit diseases, and even gnaw on wires to cause power outages or dangerous electrical hazards. These very pests, however, are the most popular meals for owls—two mature parents with a hungry, growing brood may consume 1,000-3,000 rodents in a year. As owls successfully raise their families, the local owl population will grow year after year, providing excellent pest control for generations to come.

Which Owls Nest in Boxes?

Many small- and medium-sized owls are cavity-nesters and will happily take up residence in owl boxes. The barn owl is the most well known of these houseguests, but other owls that readily use boxes include:

• Barred owls
• Boreal owls
• Eastern screech-owls
• Elf owls
• Ferruginous pygmy owls
• Flammulated owls
• Northern pygmy owls
• Northern saw-whet owls
• Western screech owls

The exact owl that may be comfortable in your nesting box will depend on the bird’s range, local habitats, the availability of other nesting sites, and the overall suitability of the box. Barn owls and both eastern and western screech owls are the easiest to attract to nest boxes.

Providing The Right Owl Box

Owl boxes are not like other birdhouses. Owls require larger homes not only because of their bigger overall sizes but also because their families can be quite large. A barn owl may have up to 18 owlets in one brood, while screech-owl families can be as large as 6-7 owlets at once. These baby birds require larger houses for safety and comfort and the parent owls need larger entrances to safely move in and out of the box as they care for their chicks.

The best sizes are:

• Barn Owls – Entrance hole 4-6” in diameter, 16” total box height, 12×23” interior floorspace; 8-25 feet above the ground.
• Screech Owls – Entrance hole 3” in diameter, 14” total box height, 10×12” interior floorspace; 10-30 feet above the ground.

Build or Buy An Owl Box

If you plan to build your own box for an owl, it is important to note that they like boxes made from weathered wood. You can find a wide variety of building plans and free downloadable details for different owl species from the Cornell Lab of Ornithology’s NestWatch site. When building your box, be sure to include ventilation holes or slats under the eaves for temperature regulation, as well as small drainage holes in the base of the box to help keep it clean. A hinged or removable side or roof is also helpful to be able to monitor the nest throughout the nesting season as well as thoroughly clean it after the owlets have left.

If you lack the woodworking skills or just prefer to purchase one instead, many online retailers offer suitable boxes ideal for owls, including The Barn Owl Box Company and Best Nest.

Whether you build or purchase an owl box, it must be mounted safely and correctly to attract nesting owls. They should always be mounted with appropriate baffles to keep out raccoons, snakes, and other raiders. Adding a layer of wood shavings inside the box can also make it more welcoming for owls and easier to clean after the nesting season ends.

More Tips For An Owl-Friendly Habitat

Even the best owl box won’t attract residents if the overall habitat isn’t suitable. Be sure to follow these suggestions:

• Do not disturb! Once owls have taken up residence the box, do not attempt to move it. In fact, barn owls are protected and you could face fines if you disrupt their nests.
• Minimize pesticide and rodenticide use to avoid removing the birds’ prey or accidentally poisoning owls.
• Minimize outdoor lighting near the nest box to help owls feel more comfortable when they’re active at night.
• Keep pets indoors at night to avoid scaring away the prey that owls will be hunting.
• Avoid excess activity near the box, as many owls are sensitive to disturbances and may abandon nests if they feel stressed.
• Keep a nearby stand of trees or small brushy area naturalized as shelter and perching space outside of the box.

Owls make wonderful neighbors, and if you put up the right home for them and take a few simple steps to make them welcome, you’ll soon enjoy the free pest control services they’re happy to provide.