SALEM (AP) — Wildlife ecologists are bracing for what appears to be the 2008 Attack of the Gray-Tailed Voles.

They’re plotting the Counterattack of the Barn Owls to stop the little wretches, who can do serious damage to Willamette Valley crops.

Jennifer Gervais, an Oregon State University wildlife ecologist, wants about 80 owls to help provide natural protection against gray-tailed voles, who appear to be massing for another assault this year.

Gray-tails, which weigh only an ounce and are indigenous to the valley, caused an estimated $35 million in damage to grass seed fields in 2005 and destroyed several million dollars worth of grape vines and nursery field stock.

“It was a pretty spectacular outbreak,” Gervais said.

Then, mysteriously, in 2006 the voles slacked off. “You had a hard time finding a live vole in the summer and into the fall,” she said.

Gervais and her associates began considering owls as a means of control after she got reports from growers that vole population was coming back.

To get ready, Gervais has erected 80 barn owl nesting boxes on the perimeters of grass seed fields near Shedd and Coburg.

Barn owls can scarf down thousands of voles a year, even more if they are feeding their young.

The nesting boxes are about 10 feet above ground and cost about $30 each.

What makes voles, also called meadow mice, such a threat is that they aren’t picky eaters.

“They’ll eat any part of the plant, and that’s part of the problem,” Gervais said. “They’ll eat foliage and also damage roots and cut seed heads off.”

Gervais said vineyard growers and nurseries probably suffered in 2005 when farmers cultivated their fields and drove voles there from their own acreage.

“Anybody who has fields next to grass seed fields wants to pay a little bit of attention. After field operations there’s going to be some voles leaving that area, and they may cause some damage on their way out.”

She said she has heard that some south Willamette Valley grass seed growers suffered losses of up to 85 percent.

“The populations swing so wildly. You’ll have a couple voles per acre going up to hundreds, maybe even thousands.”

The telltale sign of voles is small holes about the size of a 50-cent piece that are connected by surface runways.

When to start treating depends on the value of the crop, Gervais said: “At what point does the cost of treatment justify how much of the crop (the grower wants) to save.”

Some chemicals are available but must be used carefully.

Other natural predators include red-tail hawks and snakes.

Gervais and others hope barn owls will reduce the amount of chemicals needed. “They can definitely help in the fight against vole populations. They aren’t going to (single-handedly) solve the problem, but they have a role to play.

“They (chemicals) definitely have a role to play in this when vole populations get to a certain level where you can’t hope that natural predation will keep it in control,” she said.