Pop​-​up Wetlands Helping Migrating Shorebirds


Shorebirds flock at sunset over The Nature Conservancy wetland program field in Sacramento Valley, California.  The Nature Conservancy/Drew Kelly
Shorebirds flock at sunset over The Nature Conservancy wetland program field in Sacramento Valley, California.  The Nature Conservancy/Drew Kelly

The sharing economy, which has changed everything from how people get around to how they rent rooms for vacation, is even seeping into ecology. In California's Sacramento Valley, farmers are temporarily leasing flooded rice paddies to The Nature Conservancy so migratory shorebirds have a place to stop and feed while traveling the Pacific Flyway, the major north-south route that extends from Alaska to Patagonia.

The program, dubbed BirdReturns, has been in development by The Nature Conservancy since 2014 and is helping conservationists deal with the short-term needs of migrating birds. Because of urbanization, agriculture or climate change, the migrating birds have less access to wilderness to mate, feed, nest and rear their young. At the same time, the project gives farmers the opportunity to support conservation efforts — and maybe earn a little extra money — without negatively impacting crop production.

"We think it's a novel approach to stretching our scarce conservation resources to meet the needs of a changing world," says Mark Reynolds, Ph.D., lead scientist for The Nature Conservancy's California Migratory Bird Program.

During February and March 2014, the pilot season for the program, 9,600 acres (3,885 hectares) of the 494,211 acres (200,000 hectares) of rice fields were turned into shallow water for shorebird habitat. That season, the pop-up wetlands supported more than 180,000 birds, representing 57 different species. On average, the researchers found three times more bird diversity and fives time greater density on rice paddies that participated in the program compared to un-enrolled fields.

Reynolds and his colleagues published the results of a study analyzing the program in the Aug. 23, 2017 issue of the journal Science Advances.

Migrating animals, like shorebirds, are in jeopardy as their ranges cover vast swaths of land. A 2015 study published in the journal Science from researchers at the University of Queensland in Australia reported that just 9 percent of 1,451 migratory bird species had access to protected areas for all the stages of their annual cycle. In California, in particular, says Reynolds, 90 percent of the original 3.95 million acres (1.59 million hectares) of wetland habitat has been lost to agriculture and urban development.

Since The Nature Conservancy was founded in 1951, it has worked to conserve habitat by working with landowners to purchase land or permanently limit the use of their land in order to maintain its wildness. Each agreement is worked out individually, a process that's expensive and can take months or years to develop.

Reynolds and his colleagues, including Sandy Matsumoto, the team's project manager, and Eric Hallstein, the team's economist, thought the demand for purchasing migrating bird habitat could far exceed their resources. "We were looking at our habitat needs and thinking, how do we buy our way to success?" Reynolds says. "Sandy said, 'Do we need to buy [land] for the whole year? It looks like the animals need it part of the time. Eric, with his background in economics said, 'We could do a reverse auction.' I said, 'a reverse-what?'"

A reverse auction overturns the conventional role of buyer and seller. Instead of buyers competing to out-bid each other to obtain a good or service, sellers compete to offer their goods or services to one buyer at a competitive price.

How It Works

The sellers in this case are the owners of rice fields, which are typically farmed in California from April to August or May through October. During the growing seasons, the fields are normally flooded, but they're also flooded during the off-seasons to decompose the rice stubble after harvest. Reynolds and his colleagues saw an opportunity to work with the farmers to provide temporary wetland habitat for shorebirds passing through.

In early 2014, The Nature Conservancy issued an invitation to rice farmers to submit bids that itemized their costs to flood fields for four, six or eight weeks at a time beginning in February of that same year. Farmers set their own price and The Nature Conservancy was able to select the highest-quality habitat for the lowest total cost. They repeated the process in the fall of 2014, as well as in 2015, 2016 and 2017.

The farmers are very receptive to it, says John Brennan, a partner at Brennan, Jewett & Associates, a firm that manages rice sales for the Robbins Rice Company.

"To the extent that they can get their costs covered to do it, they're even more receptive because they see it as (a), something that they're excited about and a way to make an environmental difference and (b) something that really helps secure the longevity of the rice industry in California," he says.

Large flock of migrating Dunlin (Calidris alpina) in California.
Large flock of migrating Dunlin (Calidris alpina) in California.
The Nature Conservancy/Greg Golet

To figure out where and when shorebirds most needed wetland habitat for their migrations, Reynolds and his colleagues worked with experts at Cornell University's Lab of Ornithology, which collects information about birds through its citizen science project, eBird. This online checklist allows bird enthusiasts across the country to tabulate the kinds of birds they see, when they see them, how many and where.

Using data from eBird, and grant money from NASA, the Cornell team built high-powered computer models that predicated, at weekly intervals, the presence and abundance of birds at different locations. From these models, Reynolds and his colleagues created maps to visualize and prioritize where and when habitat was needed most. Once they knew the locations, they requested bids from the rice farmers.

"We want farmers to set their price and we want to be able to adjust our program based on the conditions," Reynolds says. During times of drought, The Nature Conservancy would pay more and during times of excessive rain, it would pay less, he says.

The Return on Investment

The study shows that the highest possible estimate of the total cost per year for the project was $1.4 million. That represents the average bid, and it is significantly higher than what The Nature Conservancy actually paid. "If we had to buy land equal to that area, based on current land values, it would have cost up to $150 million," Reynolds says.

The estimated cost to restore rice fields equal to that land area to wetland habitats would cost around $25 million, the report says, and maintenance fees would come in at about $100,000 per year.

Since the 2014 pilot season, The Nature Conservancy has received more than 450 bids from farmers, and they've created more than 40,000 acres (16,187 hectares) of short-term habitat for shorebirds. But the researchers stress that these pop-up wetlands are tools and not meant to replace permanent protection. If the land switched from rice farming to some other use that wasn't compatible with seasonal flooding, another protection strategy would need to be considered.

For now, rice farming and bird conservation are working hand-in-hand. "We're engaged with this community of farmers and thinking about a lot of other ways to conjoin farming and environmental benefits," Reynolds says.