For years, as California’s Central Valley grew into the nation’s leading agricultural corridor, the region gradually lost almost all of the wetlands that birds, from the tiny sandpiper to the great blue heron, depend on during their migrations along the West Coast.
But a dramatic turnaround is underway in the valley. Dozens of farmers leave water on their fields for a few extra weeks each season to create rest stops for birds. The campaign has not only helped salvage a vital stretch of the north-south migration path called the Pacific Flyway but also tested a fresh model for protecting wildlife.
The experiment is built on new research by the Cornell Lab of Ornithology, which blends the sightings of tens of thousands of birdwatchers with satellite photos and wildlife data. The combination produces digital maps so precise that they can predict when and where birds will come through, so that farmers know when to flood their fields.
“The amount of information in these maps is way beyond what any single source or even combination of sources could give you,’’ said Marshall Iliff, project co-leader of Cornell’s eBird Project. “It’s on a scale that’s never been done before.’’
At a time when 40 percent of the Earth’s 10,000 bird species are in decline, according to the State of the World’s Birds 2018 report, the still-developing eBird Project helps to remake traditional conservation.
The way eBird works is simple: Cornell collects millions of sightings from birdwatchers using the eBird app that records the location of every species spotted. It computes where birds are over the course of the year, how they move with the seasons and which species are thriving and which are struggling.
Compared with the cumbersome practice of banding birds one by one to track their travels, eBird data produce a far more comprehensive picture for hundreds of species at a time. The targeted approach is also much less expensive than alternatives: The Central Valley “pop-up” wetlands — created by paying farmers small fees to keep fields wet for a few weeks — costs 85 percent less than buying land outright, according to the Nature Conservancy.
“We might only need to protect birds, or restrict, or change the way people use certain landscapes for maybe just a few weeks during the year,’’ said Amanda Rodewald, Garvin professor of ornithology and director of conservation science at Cornell. “We now have the opportunity to dramatically transform how we approach conservation.’’
More than 400,000 birders have sent in 34 million lists of species in the United States and dozens of other countries in recent years. That makes this the largest citizen-science effort to date. Birders have reported seeing almost every species on Earth.
As the data have poured in, the research started to reveal important, concrete findings about how birds are adjusting to changing climates.
They show how species such as the American bald eagle, a major conservation success story, can be found in every state as its numbers and habitat expand. They show how other birds, such as some hummingbirds and warblers, struggle to adapt to warming trends, which are trimming breeding seasons and reducing their numbers.
Last fall, Cornell launched the stunning animated maps, which bring the migration to life by converting somewhat dry data into video illustrations that show routes birds take over the course of a year.
It’s possible to watch the huge sandhill crane work its way from Alaska and Canada across the West and Midwest to Texas and Florida. The path of the ruby-throated hummingbird, weighing about a tenth of an ounce, is shown shifting in a cloud of pixels from Canada down through the eastern United States to Central America. Another animated map shows the yellow warbler moving from the far north to Central America, passing through every state on its massive migration.
“People really get excited over the animations,’’ Cornell research associate Frank La Sorte said of the maps that so far include about 100 species. “We look at them as science. But people are seeing the beauty in it. That’s really helping to generate excitement.”
This is the time of year when birdwatchers are getting out binoculars and hiking boots to immerse themselves in the spring migration. And Cornell hopes to boost eBird contributors with the Global Big Day, the annual count scheduled for May 4. About 30,000 birders around the world are expected to join the 24-hour push that tracks the yearly numbers for species.
One who’ll be out birding for the count is Holly Merker, an environmental educator from Downingtown, Pa., one of eBird’s top contributors. “Why wouldn’t everybody be doing this?” she said. “It can make a real difference.”
Cornell’s Iliff and four other researchers were driving across North Dakota in fall 2009 when an email popped up with the prototype for a new animated map. They pulled off the road and gathered around a cellphone to watch an illustration of an Eastern phoebe’s migration travels over the course of a year.
“It blew our minds how good it looked,’’ Iliff said.
The eBird citizen-science concept emerged over 20 years of trial and error during the rise of social media and the spread of smartphones. For the first few years, the lab struggled with underpowered computers and birders who didn’t see much value in contributing.
“We were asking birders to please go and collect data so we could use it to do good things,’’ said Wesley Hochachka, a senior research associate at the lab. “We were doing it all wrong.’’
As new staff members brought technology and social media smarts to the team, they helped shape the approach to give birders back as much information as they were contributing. The eBird app now tells birders what species are around them in real time, where to find “hotspots” for birds and what species they themselves list over time.
“Birding is somewhat competitive. I’m not sure you’d call it a sport, but we realized we could tap into that,’’ La Sorte said.
Once the app became a two-way street, birdsighting contributions accelerated. Cornell gradually trained birders to keep track of how long they are out, how far they go and what they don’t see as well as what they do.
Daniel Fink, lead statistician on the eBird Project, and his team came up with ways to use satellite photos to compensate for biases in the raw data “There aren’t many birders in the winter in the Dakotas,’’ Fink said. “So we don’t have much data from there.’’
One of the biggest challenges was figuring out how to create the visualizations — and to make them both appealing and laden with information. They accomplished this by color-coding population levels, the seasons of the year and breeding and nonbreeding times.
“We put a lot of time into making them digestible and aesthetically pleasing,’’ said Tom Auer, one of the lab’s Web developers specializing in geographic information.
Mark Reynolds, a scientist with the Nature Conservancy, spent years buying land for wildlife sanctuaries in California. “But even after many, many years of that, it was really just addressing a fraction of the need,’’ he said. A century ago, the area had about 4 million acres of wetland; only about 200,000 acres remain today, according to research from a regional conservation plan.
When Reynolds heard about eBird, his team dug into the data on the flyway over California. “One member of our team said, ‘Have you thought about renting habitat instead of buying it? It looks like these birds only need this for a few weeks out of the year,’ ” he recalled.
That led to a kind of auction in which farmers and other landowners along the Pacific Flyway bid to flood their fields as the migration peaks.
In 2014, the first year of the effort, 50 farmers submitted bids to flood fields along the 450-mile Central Valley. Over the next five years, participation increased to about 100 farmers and an equal number of other landowners, accounting for about 55,000 acres of temporary wetlands. Those lands serve as crucial stopovers for birds to rest and feed during migrations that can stretch thousands of exhausting miles from Alaska to Argentina.
Reynolds said he will always remember the call he got that first year from a biologist reporting on a flooded field filled with 5,000 small wading birds called dunlin.
“We were awestruck by this number,’’ Reynolds said. “That was really heartening.”
The Cornell Lab, funded by contributions and foundations, has big plans. The lab has created maps so far for 107 species, from easy-to-spot birds such as pelicans, herons, eagles, vultures, robins, blackbirds and swallows to the more elusive warblers, buntings and kinglets.
By the end of this year, it plans to have detailed reports on 500 birds, about half of the species found in the United States and most of those that are in decline.
Broad threats to birds stem from changing weather and habitat loss caused by agriculture and land development, factors that are not likely to ease. But threats also come from airports and planes, windmills, and the urban lights that can confuse birds and throw off their migration patterns. These all make promising targets for the eBird Project.
Researchers can now advise cities, airports and energy firms of the 10 to 20 days when migration is at its height.
Andrew Farnsworth, a Cornell researcher studying these concerns, said if planes could adjust takeoff trajectories and the tallest buildings could dim lights during those short periods, the impact would be significant.
“It doesn’t have to be every day of the year,’’ Farnsworth said. “There’s a window of time right there that could be hugely valuable.’’
It’s too early to predict the full impact of the eBird Project. But the fields of the Central Valley experiment, which has been the subject of scientific studies, attracted 20 times more birds than nearby fields not in the project. The practice is now spreading to other flyways and elsewhere on the Pacific Flyway.
“I would hope we’d be able to save the lives of hundreds of thousands, if not millions of birds by what we do each year,’’ Farnsworth said. “In terms of the services that birds provide — controlling insects, pollinating, moving nutrients around — there are going to be real benefits if you think about it that way.’’
Anders Gyllenhaal is a veteran Washington journalist who writes about birds and co-publishes the birding website FlyingLessons.us.
Correction: An earlier version of this report gave the incorrect weight of ruby-throated hummingbirds. They each weigh about a tenth of an ounce.