Califonia Bountiful

A nest to feather

July/August 2017 California Bountiful magazine

Owl boxes offer shelter to beneficial birds

Take a walk with Rob Jaret around his Marin County property any given summer evening, and you're almost certain to have company. Silent in flight and stark against the dusk with their white faces and undersides, barn owls glide through the trees like spirits, peer down with their keen eyes from overhead perches and let off noisy screeches. Jaret might spot five or six of the birds a night.

"They're very unusual creatures," he said. "To me, they're the most mystical and beautiful of all of the birds."

These California natives not only project a fascinating mystique, but their voracious appetites and superior hunting skills also prove useful to their human neighbors by helping keep rodent populations in check.

Rob Jaret, a volunteer for the nonprofit Hungry Owl Project, checks on one of the three owl boxes he has erected on his Marin County property. The winged predators help keep rodent populations in check.¬†Photo: © 2017 Matt Salvo

Safe haven for helpful birds

As a volunteer for the nonprofit Hungry Owl Project in Marin County, Jaret is determined to do his part to support the birds. He's installed three owl nesting boxes on his 3-acre property adjacent to woodlands, providing habitat and shelter. He also fosters orphaned owl chicks, scaling the 15 feet to the box each night to deposit thawed mice and gophers as food. Jaret estimates he's hosted anywhere from 50 to 100 owls since he became involved eight years ago. One of the most rewarding aspects is seeing owls he's fostered return the following year to raise their own families in his boxes.

"It's just a great experience," he said. "I love doing it. I tell a lot of people it's the most fun thing that I do."

Installing nesting boxes where appropriate is an effective way of supporting barn owls, which typically nest in tree cavities. According to Alex Godbe, founding director of the Hungry Owl Project, barn owls are generally found in or near open fields and meadows, but sometimes nest in urban areas as well, especially when open spaces are nearby. Nesting boxes provide a home to owls in areas where there are fewer mature trees with large cavities, she said.

Driven by the mission of supporting the population of barn owls and promoting their use for pest control, the Hungry Owl Project installs specially designed nesting boxes in residential areas, parks and open spaces and on school grounds and agricultural land.

According to Godbe, a single family of barn owls can consume between 3,000 and 5,000 rodents in a single four-month breeding cycle. She noted the owls aren't a standalone solution to rodent control, but can be successful as one part of an integrated pest management approach, which is an ecosystem-based strategy relying on a combination of techniques to solve pest problems.

Chris Storm, director of viticulture for Vino Farms in San Joaquin County, calls barn owls a "silent partner in the vineyard." Vino Farms has installed more than 500 owl boxes on more than 100 vineyards to help control destructive gophers. Photo: Steve Adler

A silent partner

Owls can be particularly useful for pest control in agriculture. They silently patrol the night skies over vineyards, orchards and farm fields in search of destructive gophers, voles and other rodents that munch on crops, chew through irrigation lines and cause general havoc on the farm.

Chris Storm, director of viticulture for Vino Farms, is familiar with the benefits of partnering with the native predators. Family-owned Vino Farms has installed more than 500 owl boxes on their more than 100 vineyards throughout California. The winged allies target gophers, whose mounds create an uneven driving surface for tractors, interfering with farming operations. In most years, other forms of rodent control are unnecessary.

"It's kind of cool to have this sort of silent partner in the vineyard," Storm said. "That owl is patrolling the vineyard at night and I'm patrolling it during the day, so it's kind of a team effort."

The use of owl boxes for pest control has been common among California winegrape growers for about 20 years, Storm said. When he joined Vino Farms in 2006, owl boxes were already being used. Each year, they add more. Not only are the owls effective, but hosting them fits into the farm's efforts to employ an integrated pest management approach and increase biodiversity.

"If I can increase predatory raptors, like kestrels, like owls, like hawks, and insectivorous birds like Western bluebird, then I've created a more stable ecological system," Storm said. "You have more of an equilibrium between pest and prey."

Storm said the owls are a haunting, but welcome sight around the vineyards at dusk.

"They're almost a little spooky," he said. "But every time I see one, I think, 'Ah, go to work, little buddy. Get us some gophers.'"

Storm said it's gratifying to spot owl pellets, the balls of indigestible fur and bones that owls regurgitate, a sign both that rodents are being eaten and that owl chicks are thriving.

Barn owl hatchlings, left, look up at a camera mounted inside their owl box. A family of barn owls can consume up to 5,000 rodents in a single four-month breeding cycle, says Alex Godbe, founding director of the Hungry Owl Project. She poses above with Gazeau, a great horned owl the group rescued after a debilitating injury. Photo left: courtesy Rob Jaret. Photo right:¬†© 2017 Matt Salvo

Worldwide impact

Barn owls, found on every continent except Antarctica, are wide-ranging in their hunting patterns and will take up residence wherever there is a good supply of prey, said Mark Browning of the Pittsburgh Zoo. As a field researcher who has made a lifetime career of studying barn owls, he's worked in California with cooperators such as Storm, as well as in Florida, Malaysia and Israel. Browning said his research confirmed that barn owls "provide a highly effective, inexpensive and nontoxic alternative" to other methods of rodent control.

"Growers of almonds, walnuts, cherries and other nut, fruit and row crops are already using sophisticated nest box programs; sugar cane growers as well," he said. "They adapt their hunting methods, so the barn owls can be very effective in all types of orchards and other crops."

For Storm, the rewards of partnering with the birds are far-reaching. He's intrigued by the idea that what's being done on a California farm can benefit not only the farm's immediate environment and neighbors, but have ripple effects around the globe.

"These owls are one of the only species that's ubiquitous across the globe. And what we do here affects their migration," Storm explained. "The owl that's raised on our farm at Cosumnes River could end up in Florida. We're improving our farm, we're farming in a more ecological sense and we're also providing a service to others as that owl spreads out across the world, really."

Steve Adler and Shannon Springmeyer

Photo: courtesy Barn Owl Box Co.

Welcome to the neighborhood

Want to do your part to support barn owl populations? These beneficial birds of prey will return the favor by helping keep rodents in check. The Hungry Owl Project offers several tips for how to get started.

If you have a mature tree with a straight trunk or a post and sufficient open space nearby to provide hunting ground for barn owls, your yard may be a suitable location for an owl nesting box. Never install boxes on utility poles or near busy roads. Be aware that owls can be noisy in and around their nests at night. Keep boxes at least 100 feet away from bedrooms, as well as swimming pools or bodies of water. Make sure no rodenticides are being used in the area.

To build your own nesting box, you can order box plans for barn owls, bluebirds, bats and Western screech-owls from the Hungry Owl Project, available by mail or PDF. For more information, visit

For a ready-made option, the boxes sold by the Barn Owl Box Co. are lightweight but durable and capable of withstanding weather extremes. Visit Mark Browning's website at for more information.

Browning encourages anyone who's interested to get started right away.

"The moment you start thinking about starting an owl box program, go ahead and start erecting boxes," he said. "The barn owls in the area will start scoping them out immediately for potential roosts and target them for nesting in the spring."

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