Every fall an enormous avian tide washes over the Sacramento Valley. Throngs of white-fronted geese, snow geese and other birds wing their way into the valley from high in the Arctic, more than 2,000 miles away.
“We call them grinds,” says Doug Thomas, a local farmer. “As far as you can see, thousands and thousands of geese come corkscrewing in. You see these big tornadoes of birds just grinding into the fields.”
Shorebirds including dunlins, dowitchers and least sandpipers also arrive in droves. And through the winter, the entire valley—which stretches from the snow-shrouded flanks of 14,180-foot Mount Shasta to the outskirts of San Francisco—comes alive with a constant cacophony of honks, squawks, chitterings, chirps and purrs. This is the heart of the Pacific Flyway, a major migratory path for millions of birds that travel up and down the west coast of the Americas.
The Sacramento Valley is the northern half of California’s vast Central Valley, which once included some 4 million acres of wetland habitat. But over the past century, the landscape has been retooled for farming and other uses. Today, just 250,000 acres of wetlands remain, largely protected in federal and state wildlife refuges. These remnants still function as vital winter resting grounds and migratory pit stops. The Central Valley provides habitat for nearly two-thirds of the Pacific Flyway’s ducks and geese and one-third of its shorebirds, which pause here to pack on fat before they head north again to breed each spring.
“That annual cycle,” says Thomas, “all starts here.”
Now, The Nature Conservancy and its partners are working to bolster the flyway with an effort that they hope will ultimately create a million acres of wetlands here. That’s a daunting goal.
“We’re not going to save the flyway by buying farms one farm at a time,” says Mark Reynolds, lead scientist for the Conservancy’s California migratory birds program. “It’s just too immense of a challenge, and too expensive.”
So the Conservancy is testing a new program, called BirdReturns, that rents habitat rather than buying it. The program pays rice farmers to leave water in their fields for a few extra weeks at critical times during the birds’ winter and spring stopovers in the valley—effectively creating “pop-up,” on-demand wetlands. ...
http://magazine.nature.org/features/on-the-wing.xml
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