Vineyard operators in battle with bird pests
KENNEDYVLLE, Va. — Judy Crow watches from the front window of her Eastern Shore farm house as European starlings — as many as 1,000 at a time — approach her vineyard.
The birds arrive in murmuration around dawn and dusk some two to 20 times per year.
Crow grabs a plastic orange gun about the size of a water pistol and fires a loud screech into the air. The birds head upward in the formation in which they typically fly to protect themselves from predators, swarm back around and then go off in another direction.
The mid-summer quiet time for birders, when many winged creatures are nearing the end of raising their young in the intense warmth, marks the start for starlings and others of a verasion invasion that continues through the fall migration.
The Atlantic Flyway begins in Greenland and continues through coastal North America to as far as Central America. Only birds traveling from the west to access the flyway allow mountains — the Alleghenys — to get in their way.
Year-round American robins and European starlings particularly are lured by early ripening chardonnays, pinot grigios and sauvignon blancs.
These wine grapes in late August into mid-September are changing on the outside from green to gold while their starches inside are transforming to sugar.
Birds gain fructose energy from wine grapes, one of the most vulnerable crops when it comes to birds, according to Cornell University.
Where starlings remove an entire berry, robins peck at the grapes and release juice, leaving them open to insects and disease, Penn State Extension Specialist Mark Chien noted.
Starlings in flocks of 15 to 40 inches can decimate a harvest and “tear it up in half a heartbeat,” Peggy Raley-Ward, Co-owner of Nassau Vineyards in Lewes, Del., said.
Mid-Atlantic viticulturists use scare tactics in the form of balloons and sounds.
At least two have tried propane cannons.
The results of a Cornell web survey of fruit growers in New York, Michigan, Oregon, Washington and California published in May 2013 revealed that birds cause $200,000 in lost harvest and present $834 million in management opportunities.
Mid-Atlantic viticulturists net their vineyards as a primary line of defense that Virginia Tech Viticulture Extension Specialist Tony Wolf said works best.
Raley-Ward said she keeps her netting rolled up and clipped so that, when ripening begins, she simply drapes it over her trellised rows of grapes. Crow wraps hers near the bottoms of the vines, and staples them together, she said.
Netting, which is made with different mesh patterns and different strength materials, can be expensive, Tremain Hatch of Virginia Tech said.
Crow each year spends $200 per acre for her 12 acres of wine grapes, she said. Raley-Ward said she keeps hers clipped in place until the first week in August. Some birds peck around, between and through the nets regardless, Maryland Wineries Association Executive Director Kevin Atticks said.
Crow, in mid-September, discovered six who were stuck in the mesh, she said.
Bird pressure varies depending upon a vineyard’s location, Penn State’s Chien noted.
Some vineyards are located along or near the flyway, which covers much of New Jersey, Delaware and Maryland and Eastern Pennsylvania and Virginia.
Birds also gather food at places such as Bombay Hook Wildlife Refuge, Pea Patch Island and the adjacent Delaware Bay; Blackwater Wildlife Refuge on Maryland’s Eastern Shore; Assateague Island National Wildlife Refuge in Maryland and Virginia and Chincoteague National Wildlife Refuge in Virginia.
Telephone poles and wires, lampposts and fences invite roosting, Chien added.
Where Crow said that she uses her Screamer Siren gun before her netting is installed, Raley-Ward supplements netting throughout the harvest season with screeches of predatory raptors and the distress calls of more fragile species that resound from vineyard speakers.
The sounds, like decoys, are meant to encourage the birds to “keep on flying,” Atticks said.
Decoys that move and appear most life-like have proven more effective than those that are motionless, according to a Cornell report.
Those that are used in conjunction with loud sounds are most effective, the report noted.
Lasers are among the most recent bird scare tactics on the market, Hatch said, but a 2002 study found that a moving beam did not repel European starlings or cause them to disperse.
Because researchers have also found that reflectives tend to frighten birds, Jed Gray, vineyard manager at Greenhill Winery and Vineyards in Middleburg, Va., said he places reflective “Terror Eyes” balloons among the vines to frighten off birds. Bird deterrents at Greenhill were this year in place early enough to prevent any harvest loss due to birds, Gray said.
Gray and Raley-Ward said that they have tried propane cannons that fire off at scheduled times throughout the day, “but they bother the neighbors more than they do the birds,” Gray said.
Birds, once they realize that decoys and sounds do not pose a threat, tend to make their way through the vineyard in spite of them.
Mark Hinders and John Swaddle, professors at William & Mary College in Williamsburg, Va., may have a solution to that problem.
They devised Sonic Nets, speakers that emit a series of sounds that company CEO and Director Sam McClintock said interfere with how birds and pests such as raccoons, opossums, deer and foxes communicate.
“It’s like talking in a crowded room,” McClintock said. “they get tired of not being able to hear each other, and they go somewhere else.”
The cost of Sonic Nets makes it easier to defend for nurseries, airports and crops such as grapes that are considered high-density, high-value, McClintock added. The computerized speakers, available in styles ranging from omni directional cubes to solar-powered raft systems, begin at $500, extend to $5,000 and cover around one acre each, McClintock said.
Sounds available at different frequencies for different birds and mammals are audible and irritating to humans, according to McClintock.
The exception is the ultrasonic sound, which costs an additional $150 to $200 per speaker and is intended for rodents, he said.
Viticulturists can upload their own sound files, including music, McClintock said.
Chien claims that electronic sound devices have their detractors and that scary eyes, real and decoy owls and mylar tape are not very effective.
Most repellant sprays contain materials that can compromise the quality of wines while not proving effective either, he added.
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