Wetlands on Demand
In Richvale, California, rice fields stretch as far as the eye can see, and birds form flocks so dense that patches of the landscape are painted the hue of their plumage. Here, and throughout California’s Central Valley—one of the world’s richest and most productive pieces of agricultural real estate—life follows a familiar ebb and flow, for both farmers and birds alike.
For four generations, the Anderson family has worked the land here as rice farmers. While the varieties may have changed over the years, they’ve always grown just one crop: rice. That is, until this year. Now, Dan Anderson, an amiable man in his mid-30s and the latest family member to take over the family business, is breaking from tradition and doing things a bit differently. Instead of just growing medium-grain rice, Anderson is also growing habitat for sandhill cranes (Grus canadensis).
The cranes, like the farmers they share the land with, tend to be governed by tradition, returning each year with their flock to the same wintering grounds they’ve visited for generations. Tall and grey, with an impressive six-foot wingspan, they come by the thousands, filling the air with their distinct call, which is reminiscent of a French horn playing staccato notes.
Over the course of a typical non-growing season, Anderson drains his fields in August or September to harvest his crop of Calrose rice, which is then sold through a coop and exported all over the world. He chops the remaining straw and, in a process known as disking, turns the soil and stubble over to prepare for subsequent plantings. Finally, he floods the entire 300 acres, a step that helps decompose and break down the rice straw, returning its nutrients to the soil.
This year, though, Anderson is one of three Central Valley rice farmers participating in a pilot program to create habitat for migrating sandhill cranes. Instead of flooding all of his fields for duck hunting, as he usually would, Anderson has filled just 70 acres, to serve as roosting habitat. The shallow waters the cranes stand in at night help protect them against mammalian predators, which can’t approach quietly in a flooded field. Anderson has left the remaining 227 acres dry, as foraging habitat.
“You’re just adding water [or removing it] and everything else happens… It’s remarkable how readily the birds respond.”
—Greg Golet, The Nature Conservancy
The Nature Conservancy started the pilot program last year, to help the cranes survive in a shifting environment. Farmers are increasingly converting land, switching from rice to more lucrative crops such as peaches and grapes. But these crop types offer no habitat value for cranes, says Greg Golet, a senior ecologist at The Nature Conservancy working on the pilot program. “There’s a lot of concern about conversion of the crop landscape that the birds have come to depend upon,” he says.
While the available information suggests that sandhill crane populations are increasing, there’s still a great deal of uncertainty. Even with a stable or growing population, the species—which is listed as threatened by the state of California—is dependent on key stopover sites, making the birds vulnerable to habitat loss. Golet says he wants to see if birds will use sites that are at the periphery of where they’ve been historically, or in areas that can be much more resilient in the face of changing conditions.
The crane conservation pilot project is part of The Nature Conservancy’s larger BirdReturns program. Now in its third year for shorebirds, the program creates habitat-on-demand for the millions of birds that use the Central Valley each year as a critical pit stop along the Pacific Flyway, which extends from Alaska to Patagonia. Depending on the season and species targeted, the Conservancy might ask farmers to flood fields earlier or drain them later to create optimal habitat.
It’s like pop-up habitat—making conservation the next frontier for quick, nimble short-term services.
Like the farmers in the BirdReturns program, Anderson is making slight adjustments in the timing, allocation, and depth of water on his land. The cranes prefer roosting grounds in close proximity to good foraging grounds, to minimize the distance they must travel between the two. Without sufficient flooding, the birds won’t have easy access to both types of habitat they need. The combination is essential—and with four years of drought, Golet was concerned that there would be too little flooding of the rice fields, particularly during the critical winter months. “As it turns out, there’s quite a bit more acreage flooded than we anticipated,” he says. “But we wanted to make sure that if that worst case scenario came to pass, we could provide habitat in some of these historical use areas for the crane.”
Using crowd-sourced bird observations from Cornell University’s eBird database along with real-time satellite data on water availability, the BirdReturns team can determine where there’s likely to be an abundance of birds but not a lot of suitable habitat. “Then we go out and try to create additional habitat in those times and places,” says Paul Spraycar, who directs TNC’s crane program.
TNC runs a reverse auction, asking farmers to put a price on creating crane habitat. They compare predictions on where the highest-value habitat will be against each farmer’s bid, and select the farms that can create the greatest-value habitat per dollar invested. The farmers are compensated for maintaining certain field conditions and water levels, for anywhere between four and ten weeks. Simply getting a farmer to draw the water level of a flooded field down to a shallower depth, and hold it there for longer into the spring, can achieve dramatic results, says Golet.
More than 50 different species of birds have been spotted in fields enrolled in the shorebird program, with densities 30 times greater than in the surrounding landscape. “It’s just remarkable how readily the birds respond,” he says.
As winter winds down, the BirdReturns team continues to monitor bird locations and habitat conditions across the valley as they transition from the crane program to the spring shorebird program.
The short-term nature of the arrangements is a major part of BirdReturns’ success. Over the past two years, the program has created over 20,000 acres of habitat for shorebirds.
“We can act quickly through a program like BirdReturns to recruit farmers to create additional habitat in a time when it’s really needed by the birds.”
Kathryn Whitney is the former Photo Editor and Photographer for the California Academy of Sciences and bioGraphic, where she was able to combine her passions for science and photography every day. She is always ready for adventure, whether it’s outlasting a hailstorm while on assignment or galloping semi-wild horses across the Mongolian Steppe.