For millions of years, California’s Central Valley was one of the great rest stops on the planet. Millions of ducks, geese, and shorebirds funneling down the Pacific Flyway would drop into a landscape stitched with shallow lakes, marshes, and seasonal wetlands, refueling before continuing their journey. Then farms, cities, and levees moved in. Today, more than 95% of that original wetland habitat is gone, and the region’s shorebirds — among the fastest-declining bird groups in North America — have paid the price.
Now farmers are helping bring some of it back, a few weeks at a time.
Renting instead of buying
In 2014, The Nature Conservancy launched a program called BirdReturns, built on a simple insight: instead of trying to buy and permanently restore enough land to matter — a hugely expensive proposition in one of the most productive farming regions on Earth — why not pay farmers to flood their fields temporarily, right when birds need them most?
The mechanics are clever. Scientists at the Conservancy, working with the Cornell Lab of Ornithology and Point Blue Conservation Science, use millions of crowdsourced bird sightings from the eBird app combined with satellite data on surface water to pinpoint exactly where and when migrating birds are running short on habitat. Farmers then bid, in a reverse auction, on how much they’d need to be paid to flood their fields during that specific window. The Conservancy accepts the bids that deliver the most habitat value for the money.
The result is a “pop-up” wetland: a few inches of water spread across a rice field or fallow ground, mimicking the shallow marshes and prairie potholes that once covered the landscape, then drained again once the birds have moved on.
It’s paying off for the birds
The early results were striking enough to get scientists’ attention. In the program’s first years, researchers found shorebird density was roughly five times higher on BirdReturns fields than on comparable unflooded fields nearby — a huge return for a relatively short-term, low-cost intervention. In the program’s very first season, just 33 rice farmers created nearly 10,000 acres of temporary wetland habitat.
A decade later, the program has grown into a genuine landscape-scale effort: roughly 200 growers and wetland managers across the Central Valley have converted a cumulative 180,000 acres into temporary habitat, hosting millions of migrating birds along the way — everything from sandhill cranes and dabbling ducks to long-distance shorebirds like the western sandpiper, which migrates as far as Peru.
And it’s paying off for the farmers, too
This isn’t charity for the birds at farmers’ expense — it’s a genuine two-way benefit. Many rice growers were already flooding their fields after harvest to help break down leftover straw, a practice that improves soil health and reduces the need for burning. BirdReturns simply extends and times that flooding to align with migration windows, layering conservation value onto a practice farmers were often doing anyway. Farmers get paid for water they’re putting on their land regardless, and the flooding continues to deliver the same soil-building, residue-decomposing benefits — while adding groundwater recharge and erosion control to the mix.
The program is also flexible in a way permanent nature reserves can’t be. During drought years, it scales back and prioritizes the most reliable sites; in wetter years, it can expand. That adaptability matters more every year, as climate change makes both water availability and bird migration timing less predictable.
A model worth scaling further
Conservation biologists who study working landscapes call BirdReturns a rare and genuine win-win — a case where a large, intensive, single-crop agricultural system is nonetheless able to support real biodiversity, something that’s typically much easier to achieve on small, diversified farms. The Conservancy has since begun adapting the model to other crops, including tomatoes, and to other regions, aiming to eventually create up to a million acres of this kind of dynamic, on-demand habitat.
It’s a small, elegant idea: instead of treating farmland and wildlife habitat as competitors for the same acres, let the same acre do both jobs, just at different times of year. A field can grow rice in the summer and grow a wetland in the fall — and the sandpipers, geese, and cranes flying the length of two continents are counting on exactly that kind of flexibility to get where they’re going.
Source: The Nature Conservancy, “BirdReturns: Creating Dynamic Habitat for Migratory Birds,” The Nature Conservancy California.
https://www.nature.org/en-us/about-us/where-we-work/united-states/california/stories-in-california/migration-moneyball/