Barn Owls See a Housing Boom in Walla Walla, Washington

Birders, inmates, winemakers, and farmers are installing nest boxes to boost bird-powered rodent control.

The small city of Walla Walla sits among the sloping hills of southeastern Washington state, surrounded by a green and gold patchwork of wheat fields, vineyards, and alfalfa fields. Last winter, Blue Mountain Audubon Society began working with the nearby Washington State Penitentiary to build and install nest boxes for climate-threatened Barn Owls. The chapter provides the plans and funding for materials, penitentiary inmates build the boxes, and the chapter installs them on area vineyards, farmlands, and residential properties near appropriate habitat.

Chapter president George Jameson says the project’s goal is to increase populations of Barn Owls, reduce the use of rodent poisons that harm birds and other wildlife indirectly, and educate community members about more bird-friendly ways to protect crops from rodent damage. The nearby Blue Mountain Wildlife rehabilitation and education center in Pendleton, Oregon, regularly treats owls in various stages of rodenticide poisoning, and it’s not always possible to save these birds. In contrast, putting up nest boxes is an effective way to attract owls and other raptors to agricultural areas. Jameson says owls are a perfect fit to benefit alfalfa, wheat, and grape growers because they eat large numbers of rodents that can destroy crops, nibble at the roots of grapevines, and disrupt fields by digging networks of burrows. By one estimate, he says, a pair of Barn Owls and their chicks can eat 3,000 rodents a year. “Barn Owls can take a gopher in pitch-black,” he says. “They don’t even have to be able to see it, their hearing is that acute.”

Thus far, the participants in the program have built and installed 42 Barn Owl nest boxes in the Walla Walla area (see map), drawing on information from the Hungry Owl Project in California. The chapter is monitoring the boxes to see which birds are using them—a number of Barn Owls have moved in and so have a few kestrels, which is perfectly fine, Jameson says, considering that kestrels eat plenty of mice and voles. The boxes are about two feet by two feet large, built from plywood with a double roof painted white to help reflect heat in the summer. Recent summers have brought unusual heat waves to the area, which have spurred more conversations with vineyards about climate change and its impacts on grapes and owls alike.

One local vineyard, Pepper Bridge Winery, hosts about a half-dozen boxes on its fields and neighboring homes of the winemakers. Jean-François Pellet, general manager and winemaker, has a longtime interest in environmental issues; Pepper Bridge is certified sustainable and recently installed solar panels that provide most of its electricity. The winery doesn’t use herbicides or rodenticides, but it still needs to control gophers and mice, such as with traps. Left unchecked, gopher mounds will make it difficult for their tractors to get around, Pellet says. He’s seen a few Barn Owls by the nest boxes so far and hopes to see more.

Blue Mountain Audubon plans to install more nest boxes depending on interest from landowners and donors, and it will maintain and clean out the boxes each year, a task that requires a respirator and rubber gloves. “They are the messiest thing you’ve ever seen,” Jameson admits, describing the mishmash of excrement, small animal bones, and usually dead owl chicks littering the bottom of the nest.

The project is also already drawing interest beyond the city of Walla Walla. The penitentiary included an article about the project in a sustainability newsletter that goes out to all state penitentiaries; a correctional facility employee in Spokane saw it and contacted Blue Mountain Audubon. In return, the chapter sent him information so he can install two Barn Owl boxes where he lives to help the birds establish habitats all over the eastern part of Washington.