FRESNO, Calif. — Farmer Don Cameron spent more than half a million dollars on drip irrigation to save water and grow better tomatoes. But gophers soon began chewing his drip lines, threatening to ruin his investment.
He waged a losing war using gopher traps until he had a serendipitous conversation with the Fresno Audubon Society. Cameron, a bird lover, called the society to report sightings of interesting species at his farm. His gopher problem came up, and Audubon had a solution.
Soon, more than a dozen families of barn owls were snatching gophers from Cameron’s fields near Helm in west Fresno County. The birds have taken up residence in wood nesting boxes atop of tall poles. Audubon helped Cameron get the boxes.
Enlisting owls to hunt down pesky gophers is nothing new. The real news is that farmers and environmentalists are getting together to expand the idea.
“It’s a good partnership,” Cameron said.
Audubon officials agree, saying they want to bring back the owls and some other birds that decades ago lost nesting trees as farming and development spread.
Farmers and environmentalists don’t usually collaborate in the San Joaquin Valley, often battling over pesticides or groundwater. The valley’s major farm-environmental collaboration - the restoration of the San Joaquin River - happened only after 18 years of court battles.
But the gophers might have bridged the differences simply because they have become real pests in the past few decades, damaging crops and irrigation lines.
In the 1990s, researchers found that gophers are at the top of the barn owl’s menu, which includes all kinds of rodents.
Federal scientists later estimated an average family of barn owls can kill 1,500 to 3,000 rodents a year. All the owls needed was a place to call home. Without trees, nesting boxes made sense.
The boxes now appear in many valley locations, usually atop poles up to 20 feet tall. The boxes are generally about 2 feet high, 2 feet wide andabout 18 inches deep. There are many designs, and construction materials include wood, plastic and aluminum.
Fresno Audubon president Brandon Hill says other birds - wood ducks, tree swallows, burrowing owls and kestrels - would benefit from an expansion of nesting boxes.
Cameron and others, such as Southern California Edison Co. and Moss Lumber Co., have made donations of money and material to Audubon in the past year, Hill said.
Audubon’s campaign started only a year ago. Already, it has yielded about 100 nesting boxes and a handful of interested farmers.
This is Cameron’s first year using the boxes. He has 40, about 15 of which are occupied. He expects more owls next year.
“It’s not going to wipe out all the gophers on my land,” said Cameron. “There must be hundreds, maybe thousands of gophers out here. But we’ve seen quite a decrease in damage.”
Gophers, like most rodents, are gnawers, mainly because their teeth grow continuously. They need to sharpen and maintain them.
The creatures discovered Cameron’s drip irrigation lines 7 inches below his tomatoes and began chewing holes in them. He was forced to dig up the lines for repair or replacement. He paid thousands of dollars to hire pestcontrol workers who set traps in his fields.
But the owls are a more elegant solution, he found. Owls sweep silently through the fields at night, locating rodents by sound even when the prey is not visible. And they have a big appetite.
Biologist Jeff Davis, who advised Fresno Audubon on the project, said he was amazed at how many gophers had been killed by owls when he installed his own nesting box.
“At the end of nesting season, I went in to clean out the box,” he said. “I counted 289 gopher skulls inside.”
Barn owls are cavity nesting birds, meaning they prefer to set up nests in tree holes where they raise their young.
The kestrel, a small hawk, needs a lot of help too, he said. Many of their prime nesting trees - cottonwoods and willows - have disappeared.
“Kestrels are not doing well,” said Davis, who is based in Fresno with H.T. Harvey and Associates Ecological Consultants. “Working with farmers is a good way to help them, too.”
Front Section, Pages 3 on 06/28/2010