Grower devises new method
of applying bird nets
Netting is attached vertically to the sides of each row.
BY MELISSA HANSEN
When the inexpensive and easily installed methods for bird control in vineyards no longer work, it's time for last resort efforts, -- netting. A creative Walla Walla, Washington, vineyardist built a better "bird trap" by putting bird netting on the side of the vine row instead of over the top.
Birds can be a real problem to high dollar wine grapes, especially those yielding only two to four tons to the acre. With such low tonnage, vineyardists aren't willing to give away much fruit to birds. Netting, while effective, is expensive and time-consuming to put on and take off before harvest.
Manager of Pepper Bridge Vineyard Tom Waliser, who describes his bird problem on a one to ten scale as “seven to ten," wanted to reduce the cost and improve storing and handling factors of over the row bird netting. He devised a method which uses one-third of the netting material and is easier for employees to handle.
"I looked at netting machines which lay netting over the vine row" Waliser said, "They are effective, but I've got a lot of acres to cover, and cost was a factor." As an alternative, he cuts his netting rolls into thirds and drives down the middle of the row with a tractor, installing netting vertically on the sides of vines. Workers walk on each side tying and clipping the netting to trellis wires and cross arms. The 4.5 feet wide netting protects the fruiting zone on each side of the vine he added. Birds can get up inside the netting, but have so little room that they spend all their time trying climb back out. For removal the tractor three-point lay-out device turns counter or backwards to roll the netting up after harvest.
He's able to leave the netting in place during harvest because grapes are picked by hand at Pepper Bridge and the netting is easy to lift out of the way. However, netting would need to be removed for those grapes mechanically harvested.
Waliser said he nets about half of their acreage. Other bird control devices are used on the other half. He estimates that the netting costs $30 an acre to install and remove, reeling up the netting takes a little more time. Total acreage cost for netting, projected over four to five years (expected life of netting is around $200 per acre. Netting on the side has worked well for vineyards with tight canopies, such as those with vertical shoot positioning and Smart Dyson trellis systems. He hasn't tried the side netting on a sprawl trellis system, but believes it would probably require, overhead netting. Years of birds feeding in his vineyard have taught him that they typically show up after veraison and quit feeding about two weeks before harvest. Therefore, he installs the nets after veraison.
Waliser uses netting in his problem areas, particularly those located near houses where propane cannons are not welcomed by neighbors. In the acreage where neighbors are not an issue, he uses a variety of bird deterrents, including computerized animal noise, balloons, tape dangled from wires, plastic owls and hawks, and mechanical noise-makers.
"When you just use one aspect, they fail individually. But when you put them together, they are much more effective," he said. Initially, bird damage wasn’t much of a problem and was limited to a small area of about 15 to 20 acres. As the vineyard expanded, birds became more of a problem. Propane cannons worked to scare the birds away, but they made more noise than the neighbors were willing to tolerate. Robins make up the majority of his bird population.
“We did like many others have done, we planted the orchards before the vineyard, which just gave the birds a place to live," he added.
Waliser is pleased with their netting system. The machinery is simple to design and using one-third less material makes it easier to put on, take off, and store.
"We realize we can't net all of our acreage. We don't have the time or money to do so, but if you pick the worst area, netting can be the ultimate solution," he concluded.
(From the March 15 2001 issue of Goodfruit magazine)
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