Shortly after the Cedar and Harris fires passed through our property the Barn Owls returned. I speculate that their seasonal migration came early because their second home was destroyed by fire. Since that day they have become year round residents, producing their usual two clutches per season. Our East county foothill property has become home to not only the parents but also an extended family of Barn Owls. It is not uncommon to count five to seven owls just after sunset hunting and feeding well into the evening.
The project started over five years ago as an effort to curb the rodent population especially targeting gophers. Of the many gopher traps on the market we’ve had limited success. The gophers seem to learn to avoid the traps and cover them up, then there’s the issue of dead rodent disposal. When, done correctly becomes a routine requiring as much attention as the setting, checking and re-setting of traps, needless to say a dedication of time and patience.
I first observed Barn Owl Houses in the Northern California wine country of Napa and Sonoma. Then again later in other locations of San Diego county. A small amount of research provided requirements and specifics for constructing a Barn Owl House. Another item along with the BOH is a predator perch. The perch works as a platform for the owls to hunt from as well an aid for young chicks to develop their flying and hunting skills.
Having raised pigeons as a young boy taught me some do’s and don’ts in terms of nest boxes. Which is essentially what a BOH is. Using information from others and adding from my boyhood experience I constructed two identical BOHs.
Size matters as far as floor area and entrance hole diameter. There should be enough room for the owls to stand and turn around, and the entrance hole should be not so large in diameter as to provide access to the owl’s natural predators. The two BOHs were constructed with the entrance hole offset to one side. This is for two reasons, the entrance perch is extended through the entire house from front to back. The area beneath the perch is floor-less. This allows the owl an area to roost, watch their young and allows droppings to fall onto the ground below.
The remaining half of the BOH is the nest box. This area has a small curb parallel to the perch which keeps the eggs from rolling off the floor and down the dropping hole. The barn owl will lay about 5 eggs. There is also a door located on the outside wall opposite the curb for cleaning. Periodic cleaning and inspection of the nest box revealed chick droppings and no nesting materials; twigs, branches, straw, ECT.
The BOH is built with two roofs, the first being an integral part of the house itself. The second is the working part, utilizing a no-maintenance sheet metal top which sheds water. The two roofs are separated with an air space between them, this non-direct contact between the interior ceiling and exterior roofing create a thermal barrier providing some comfort to the occupants. Very similar to present day home construction.
The two identical boxes are by design. Barn owls will produce two clutches per season. After the first clutch has reached juvenile status and can fend for themselves. The parents move on to produce a second clutch. This has benefits to both the owls and myself. The owl can set up in familiar surroundings between 600-900 ft away, and still check on their offspring.
I benefit from the continued hunting from these amazing birds. Each adult owl can catch and consume on average five rodents per night. While on eggs the male is the sole hunter. Both BOHs are posted in exactly the same compass direction as well as height.
