BOWMAN COUNTY, N.D. — There’s a stretch of Kim Shade’s ranch in the North Dakota Badlands where he used to look for a peculiar long-billed bird from the seat of his saddle. Now, all he sees there is a road leading to an oil rig.

“I used to see quite a few of them,” the cowboy said of the speckled, chicken-size bird called a long-billed curlew. The curlew’s absence is unsettling, he said.

“Our birds on the prairie are the same thing as a canary in a coal mine,” Shade said. “If we lose them, something’s wrong.”

Curlew territory has been slowly shunted westward in North Dakota following the retreat of the state’s dwindling grasslands.

That’s bad news for conservationists trying to salvage one of the country’s most threatened habitats, which has been hit hard by industry and crop development. It’s also a problem for ranchers, whose cattle rely on the health and sprawl of prairie as much as the curlews do.

So over the past year-and-a-half, scientists strapped GPS trackers to 15 curlews in North and South Dakota to figure out whether and how far they are being pushed from their remaining pastures. Researchers already have this and last year’s migration data, which tracks the paunchy birds’ flights south to Texas and Mexico.

As the data grows with each year’s migration, the scientists will have a clearer picture of where the curlews stop to nest. The bird is an indicator species, they say, which means the curlew flight map will also help identify areas of importance to a host of other grasslands-reliant species, including cattle.

“What’s good for the bird is good for the herd,” said Kevin Ellison, program manager at American Bird Conservancy and point person for the North Dakota part of the curlew project.

Most remaining grassland is privately owned, which leaves it unprotected and open to development, Ellison said.

Only about a quarter of North Dakota’s original grasslands remain unfarmed or undeveloped. More than 2 million acres are plowed up each year in the Great Plains,

which stretch from southern Saskatchewan and Alberta in Canada south to the Gulf of Mexico, according to a 2021 World Wildlife Fund report.

Farmed cropland isn’t good enough for many grasslands birds, because traditional agriculture destroys biodiversity in the soil and pesticides rob the ground of the tiny invertebrates that feed the birds.

But ranchers own or use a lot of the remaining grasslands, which makes them de facto stewards of curlew country and crucial partners to conservationists.

“These birds are just using their land,” said Sandra Johnson, conservation biologist for North Dakota Game and Fish, which uses state tax donations to fund the curlew-tracking project at about $20,000 each year.

And it is good land where there are cattle, said Johnson, because the animals imitate the grazing habits of bison that used to roam the region in the millions. Healthy grasslands wither without regular grazing and hoofs

kicking up the dirt, she said.

When ranchers go the extra mile to move their herds before they overgraze a field, or plant and tend native grasses, “it’s really showing a lot of great benefits for birds,” Johnson said.

Curlew numbers have stabilized in the past 20 years, excluding them from the U.S. endangered species list. There is no recent curlew-specific population study, said Jay Carlisle, who has been tagging curlews since 2008 as research director for Intermountain Bird Observatory at Boise State University.

The best estimates come from the U.S. Geological Survey’s North American Breeding Bird Survey, which tallies them at anywhere from 50,000 to 123,000 birds.

What’s more revealing than a head count is where the curlews migrate and nest, hence the tracking project, Carlisle said. Curlews used to breed as far east as Indiana. Now, the southwest corner of North Dakota marks the easterly edge of their breeding territory.