A team at Humboldt State University is attempting to prove that owls can be as effective as rodenticide at protecting grapes.

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When talking about a fine California wine, drinkers will discuss everything from the soil to the fruit to the winemaker's deft hand. But here's one little guy that often gets overlooked: The owl that protected those vines from rodent attacks.

Bay Nature magazine recently highlighted the research being conducted at Humboldt State University's Department of Wildlife under professor Matt Johnson. Graduate students in his lab have been investigating the impact of birds — mainly owls — on California vineyards as a more ecofriendly option instead of using rodenticides. Out of the 75 wineries the lab surveyed, about 80 percent of them say they now use owl boxes in an attempt to control rodents, especially gophers, and Johnson explains that the Napa Valley alone has over 300 of these boxes which, if set up properly, will naturally be turned into new homes by owls native to the area.

Barn owl sitting on a rock
Credit: Getty Images

"There has been an upswing in the use of nest boxes in California's winegrape vineyards — not just in the Napa/Sonoma area, but in other regions as well such as the Central Valley," Johnson told me via email. "Interestingly, the use of barn owl nest boxes is also being used in other areas and for other crops around the world such as in Israel (alfalfa and other crops), Malaysia (palm orchards), Kenya (mixed vegetables), Spain (olive, etc.), and central California (pistachio & fig)."

A team of three graduate students from the lab reportedly monitors upwards of about 280 of these nest boxes across 65 different vineyards and an owl family in each nest can apparently feast on an average of about 3,400 rodents each year. The primary goal of the lab's research is to prove that these owl boxes truly do reduce the number of rodents — something they say they haven't conclusively achieved yet — but what they have found is that farmers who use these boxes also use less rodenticide.

"Whether the use of barn owl boxes caused that reduction in rodenticides is, of course, not proven," Johnson was quoted as saying. "Nonetheless, this result is encouraging."

Regardless, the ease with which owls are willing to set up shop on vineyards seems to make it at least worth a shot. "You can literally put a barn owl nest box in the exact location where you think you have a problem with the small mammals, and voilà! The owls will start using that area," John C. Robinson, a Bay Area-based ornithologist, told Bay Nature.

Though to be honest, if you offered me a free house next to a winery, I'd probably do the same thing.