A Coalition of Science-Based Wildlife Professionals


Some boxes, if mounted where predators can access them, become a problem in and of themselves. Even though barn owls are birds of prey, it’s important to also recognize that these birds have predators. It is critical that when deciding where to place barn owl boxes, an awareness of how a predator could access the box be considered. Boxes that are placed in trees, on barns, or on other structures that predators like raccoons and opossums can climb are potentially open to predation. We recommend mounting your box to a high, slick, metal pole that would be difficult for a predator to grip and climb. It’s also important to place the box away from trees or any other high object that could grant a predator access by climbing and jumping to the box. Our team of wildlife professionals can assist you in choosing the perfect location for your barn owl boxes.


When it comes to predation, it’s not only where the box is placed that should be considered. Equally important is the size of the entry hole. You may not think that something as simple as an entry hole could be so important to owl box design; however, proper placement of the entry hole is imperative to the safety of the owls. In order to deter potential predators, the entry must be at least 4" but no greater than 6”. We designed our entry holes in a unique “oval” shape that ensures Great Horned Owls can’t be granted access, while still allowing entry to the barn owls. Our boxes also have a security shield installed inside. This ensures that the owls will have a place of refuge should Ravens and Hawks poke their head in to investigate. Placing the hole at least 16 inches high from the bottom of the box ensures that there will be adequate protection from rainwater, falling from the box, or being pushed out.




Solution: Purchasing your box through a member of The BOMP Coalition Project will ensure that your box will meet predator-proof criteria. In addition, you will be working with wildlife professionals who will be able to assist you with box placement and consult with you on potential threats in regard to predation. Should you decide to purchase through another vendor or build your owl box, we recommend you consider all the information in this article. Avoiding adding perches to your box, adhering to entry hole recommendations, and using a pole mounted box are all critical factors to consider in your purchase and/or building plans. There are some “hawk perch” styles of barn owl boxes out there that are attached, or, in close proximity to, the nest box. This style should never be used, as it attracts hawks to sit and become accustomed to this perch for hunting. The problem with this is that the owlets inside the box will vocalize and attract the predator instincts of the hawks. Once the owlets begin to fledge, they are easily preyed upon by hawks that have grown accustomed to this perch and are waiting for the opportunity to catch the “easy” prey.

BOMP Coalition Administrative Office and Contact Information

Mailing Address:

Sonoma County Wildlife Rescue

PO Box 448

Cotati, CA 94931

Physical Address:

Sonoma County Wildlife Rescue

403 Mecham Road

Petaluma, CA 95452

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