The birds of prey that stand guard over California’s vineyards

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three raptors in light drizzle falling over Bouchaine vineyards in California’s Napa Valley. Rocky, a beefy Harris falcon with long, white-tipped tail feathers, gently smooths his mottled wings while EB, a hybrid Barbary and Saker falcon with a speckled white and brown chest, keeps his gaze fixed on a row carefully braided vines. Hootbert’s eyelids flutter sleepily over his large yellow bespectacled owl eyes.

The trio are the first line of defense against the invading armies of starlings, red-winged blackbirds and familiar finches that feast in the ripening Bouchaine vineyards each summer and early fall. Falconer Rebecca Rosen is the general leading them into the fray.

From July to October, as the grapes ripen, small birds are attracted to their sweet, sweet juices. “You can see them in the morning moving from vine to vine to vine, these massive mega herds that can totally devastate the crop,” says Rosen.

Falconer Rebecca Rosen (pictured here with a 17-year-old falcon named EB) started Authentic Abatement in 2003 to help protect Napa Valley vineyards from small birds that eat the grape harvest.

Flying birds of prey twice a day over the nearly 90 acres of planted Bouchaine vines effectively scares away avian intruders. The mere regular presence of predators with sharp claws and dagger beaks is enough to contain the voracious hunger of the herds.

Destruction of wine crops by pest birds is an ongoing problem not only in Napa Valley, but in wineries around the world. Growers have developed a number of techniques to control the herds. Some hang strips of light-reflecting mylar in the vines or float hawk-shaped balloons above them. Others drape vines in netting or fire bird cannons, propane-powered devices that scare and disorient small birds with regular 125-decibel blasts. None of these methods are particularly effective, explains Chris Kajani, winemaker and managing director of Bouchaine.

“You can literally watch the birds move before the cannon goes off and come back when it does. They know,” she said. “But birds are very, very aware of a raptor nearby. Not only does that really mitigate bird damage, but there’s no litter in your vineyard. [from torn mylar strips]no fight with your neighbor [over the noise of the cannon]no need to use propane.

Each bird Rosen flies has its own personality.  Hootbert, a 3 year old owl,
Each bird Rosen flies has its own personality. Hootbert, a 3-year-old owl, “loves kids,” she says, and regularly watches TV with Rosen’s family.

Although hawks and sparrowhawks have been employed lucratively by mankind for thousands of years, their use in the wine industry is relatively new. The estate was just beginning to grow when Rosen traded her job as a cocktail bar waitress for a leather falconry glove in 2003. Her business Authentic Abatement now protects valuable vineyards – Napa’s wine grape harvest was worth more than $476 million in 2020. — at more than half a dozen Northern California wineries.

Rosen trains her birds using science-based positive reinforcement techniques, she explains in Bouchaine’s garden. Each species of raptor is a different tool in its toolbox for dealing with invasive flocks. “Hawks launch projectiles,” Rosen says. “The owl is stealthy, an ambush predator…hawks are impulsive birds, they just sort of go for it.”

Each bird also has a distinct personality. Pillboy, a peregrine-barbary-gyr cross that Rosen added to his flock in 2018, is what they call a hot bird, “which means he’s got tons of energy. [and can be] a bit difficult to manage when it’s not flying regularly,” she says. “We decided to name it Pillboy after a character from the show The right place because he has the personality of someone who has blown too many rods.

Rocky stands guard on a post in front of the Bouchaine Winery fields.  At other vineyards, you might see a hawk-shaped balloon in the sky or hear a steady cannon, both of which are meant to scare away pest birds.
Rocky stands guard on a post in front of the Bouchaine Winery fields. At other vineyards, you might see a hawk-shaped balloon in the sky or hear a steady cannon, both of which are meant to scare away pest birds.

WeeMan and Mammas Boy, two Harris Hawk brothers who joined the flock in 2019, used to fly together, but Rosen is working to build Mammas Boy’s confidence in hopes she can train him to be a falconry school bird. “He stays very tight and follows me,” she explains. “Right now, I’m trying to convince Rocky to help him with his shyness. Harris Hawks are like dogs, they learn much faster from each other and love to fly together.

Rosen bends down to offer EB the hawk a perch on his gloved hand. EB’s short, caramel legs are designed to kick prey through the air. The tomial tooth of its beak, a protrusion from the upper beak, severs the vertebral column. She flicks her wrist and EB takes off in a wide arc around the basement. It hovers for a minute, a small dot in a wide open sky, and then Rosen begins swinging a decoy to pull the bird out of the clouds. Seconds later, he lands gently on his glove and lowers his beak to tear a day-old dead chick from his hand, his reward for a job well done.

The goal of falconry-based reduction is not to harm pest birds, but simply, in Kajani’s words, to “bring the fear of God to them”. When Hawks and Falcons are in full work mode, they can patrol acres and acres of vineyards faster and with more agility than anything in the field ever could.

Each bird has its own hunting style.  Hawks like Rocky
Each bird has its own hunting style. Hawks like Rocky “are impulsive birds, they just go for it,” Rosen says. But the birds of prey in Rosen’s flock are meant to scare, not harm, smaller birds.

Rosen and his team track their birds with a radio telemetry app that reports their location and speed in real time. She clocked her peregrine falcon last year at 169 miles per hour; in the wild, they can fly about 100 miles per hour faster. Technology is a “lifeline,” Rosen says. “It’s rare to have a bird that doesn’t want to come back but [with the app] I can find them instantly. This cuts the recovery time to nothing,”

In the garden, Rosen turns to Hootbert, the spectacled owl. She has raised this bird since he was a chick and he is now part of the family. At home, he watches TV with his kids (“Hootbert loves kids,” Rosen says) and when she makes the long drive to Napa Valley each season, he rides next to her in the passenger seat. The falconer lifts a dead chick and asks Hootbert to fly towards her from her perch. He’s not moving.

“He’s very patient,” she laughs. “Owls will wait for a bird or mouse to fall asleep before attacking. They don’t want to expose themselves,” Rosen explains. Several tries later, the obnoxious bird flies away, its massive eyes shining like golden orbs.He nonchalantly lands on Rosen’s glove like he’s doing her a favor and rips her chick apart enthusiastically.

Protecting the vineyard is big business.  In 2020, Napa Valley's wine grape harvest was worth more than $476 million.
Protecting the vineyard is big business. In 2020, Napa Valley’s wine grape harvest was worth more than $476 million.

Not all vineyards experience the same level of destruction from pest birds. “Some, like Bouchaine, just take the hit,” Rosen says. The neighboring Carneros appellation vineyard owned by Cakebread Cellars is also directly in the summer flight pattern of starlings and other small birds. Literally millions of grapes are ripe for picking each summer. Rosen’s falconry-based reduction helped keep them on the vine.

“We moved into falconry because we thought it was a great, sustainable way for us to keep pest birds from being a problem,” says Aaron Fishleder, Vice President of Operations at Cakebread. “Making the falcons fly is beautiful and incredibly effective.” Additionally, getting rid of ugly mylars and noisy cannons benefits everyone in the community.

While many reduction methods, such as light-reflecting mylar strips, can be unsightly, birds can be a nice addition to vineyards.
While many reduction methods, such as light-reflecting mylar strips, can be unsightly, birds can be a nice addition to vineyards.

“I wish more of our colleagues in the valley would use this method,” says Fishleder. “We really like it and hopefully we can help our [wine growing neighbors] inadvertently. I can’t imagine us moving away from falconry.

Perched in Bouchaine’s garden, EB and Rocky are content to quietly digest their fresh chicks in the humid morning air; Hootbert falls asleep again. Today was an easy day, but in just a few weeks, when the grapes start to swell with sweet sugar, they’ll be back to full-time work. Until the early fall harvest, there will be no rest for the guardians of the Napa Valley vineyards.

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