This article was created in partnership with the National Geographic Society.

In late June our floatplane lifted off from Deadhorse, Alaska, at the top of the state, and arrowed west. As it gained altitude the industrial spraddle of the Prudhoe Bay oil field shrank beneath the plane’s pontoons. Soon there was nothing below but land the color of wet cardboard, an earth still waking from its long winter.

About 110 miles to the west, the plane skidded down on a half-frozen lake. We pitched our tents and ringed the camp with an electrified bear fence against curious grizzlies. Then, Martin Robards and Peter Detwiler—a scientist and a senior field technician for the Wildlife Conservation Society, respectively—headed out across the tundra. Robards wore a Remington 870 shotgun slung over his shoulder (bears, again).

The tundra was treeless and stretched until the eye watered. What appeared to be solid land was either as soft as a cheap mattress, or the consistency of pudding. Detwiler wore hip boots; Robards, fishing waders.

View Images Canada geese and brants swim in the icy waters of a wetland in Qupaluk, on Alaska's North Slope. They are just offshore of a brant nesting colony, established in the safety of this arctic wetland. Photograph by Kiliii Yüyan

They were looking for birds.

The men were standing on the biggest patch of public real estate you’ve never heard of: the National Petroleum Reserve-Alaska, or NPR-A. The reserve is the single largest piece of public land in the United States. Every spring, ducks, geese, owls, and shorebirds of every kind—millions of them—descend from all corners of the planet to rest, mingle, mate, lay eggs, and raise chicks, before dispersing once more around the world. For birds, it has been called “Heathrow at the top of the world.” The entire Coastal Plain of Alaska has the densest concentration of birds in the Arctic.

As the Trump administration continues to push for more oil and gas extraction on public lands, the petroleum reserve is on the cusp of profound change. The week’s trip for this two-man research crew was the start of a years-long project to detail precisely what bird life is here and how it uses the place, and to try to guage what such change would mean.

National Petroleum Reserve–Alaska CANADA Alaska (U.S.) Point Hope N Chukchi Sea 100 mi 100 km National Petroleum Reserve–Alaska Smith Bay TesheKpuk lake special area Nuiqsut Trans-Alaska Pipeline Deadhorse Prudhoe Bay Arctic National Wildlife refuge Beaufort Sea UNITED StateS CanADA Oil and gas development Leased tract, December 2017 Field Pipeline JOHN KAPPLER, NG STAFF Oil and gas development Leased tract, December 2017 Field Arctic Ocean Pipeline Alaska CANADA (U.S.) 100 mi 100 km TesheKpuk lake special area Smith Bay Nuiqsut Prudhoe Bay Camden Teshekpuk Bay Lake Chukchi Sea Deadhorse National Petroleum Reserve–Alaska Arctic National Wildlife refuge Point Hope United States Canada Trans-Alaska Pipeline Kotzebue JOHN KAPPLER, NG STAFF

"This is the best of the best, and we really want to document the nuances within that,” Robards said.

The men walked slowly across the tundra, scanning the ground for two bird species they needed to place tags on, pectoral sandpiper and red phalaropes, to better understand their migration patterns. When one of them flushed, they tried to find the nest it had left—a surprisingly hard thing to do, even among sedges that grow only shin high. They located a red phalarope’s nest.

Detwiler set beside it a net that would spring over the nest. He paid out a trigger cord. Then we walked some distance away, laid down on the wet turf…and waited for the bird to return. And waited.

“Welcome to ornithology,” said Robards.

View Images Scientists attach a satellite tag to a pectoral sandpiper at Qupaluk, which is at the intersection of two major migratory bird flyways. Photograph by Kiliii Yüyan

Eventually the male red phalarope appeared and settled back on the nest. Detwiler pulled the cord. The trap sprang. Running to the nest, he took the bird gently in hand. It was a handsome little creature, with a chunky, rust-colored breast and a bill the yellow of a No. 2 pencil.

The men weighed the bird. They took measurements—of the wings, of the bill. They plucked feathers for analysis. Finally, they wrestled the bird into wearing a tiny “backpack,” a transmitter with a tiny solar panel and antenna. The backpack cost $4,000 and weighed less than a bottle cap. it would talk to a satellite, providing researchers with detailed information about the bird’s migration.

They let the bird go. It waddled off, unsure of itself. Then it flew away.

A brief history

View Images An oil drilling rig rests on the tundra west of Prudhoe Bay. Photograph by Kiliii Yüyan, Earth Justice

President Warren Harding established the petroleum reserve in 1923 as an oil supply for the U.S. Navy, years after native Alaskans first showed Yankee whalers oil seeping from the ground. For decades, however, no commercial drilling happened. In 2015, the first commercial oil development began on native lands in the far east of the reserve, and is continuing on others. The state of Alaska and ConocoPhillips, the state’s largest oil and gas producer, want more land opened to drilling. Some native groups, including those who benefit from drilling money, also want fewer restrictions on the land.

Proponents saw their opening in the Trump administration, which is now retooling the reserve’s Obama-era management plan. That plan had allowed drilling in about half of the reserve but set aside five “special areas” for some protection, in part because of their value to wildlife and subsistence hunting.

“We're working now with the state of Alaska and the local government, the North Slope Borough, to redevelop an integrated activity plan in the region that will make millions more acres available for leasing,” Joe Balash, the Interior Department's assistant secretary of land and minerals management, said last year during a speech at the conservative Heartland Institute. (Balash announced a few days ago that he would leave the administration to join a foreign energy company that operates on Alaska’s North Slope.)

Of particular interest to ConocoPhillips are areas of the reserve near Teshekpuk Lake, a massive, shallow lake system in NPR-A’s northeast corner that’s larger than Lake Tahoe. It also happens to be ground zero for migratory birds in the Arctic, which are already being squeezed by other factors, including climate change and loss of habitat in the places they stop elsewhere around the world.

“The last thing we need right now is a new impact hitting them,” said Robards, the regional director for the Wildlife Conservation Society’s Arctic Beringia Program.

Birds under pressure

Out on the tundra, Robards stopped. “Let’s do a point count,” he said. He lifted his binoculars and glassed the horizon. Beside him, Detwiler scribbled down notes.

“Two pomarine jaegers.”

“Two pecs”—pectoral sandpipers—“at 100 meters.”

“Three more pecs. Same place.”

“LaLo”—a Lapland longspur—at, like, 70 meters.”

View Images An arctic tern surfaces after fishing in the waters of the Qupaluk wetland area. This region is of critical importance to nesting bird habitat. Photograph by Kiliii Yüyan

In five minutes the men had tallied dozens of birds and waterfowl. Even so, Robards sounded almost apologetic. “This is pretty quiet for up here.”

Even as the Arctic National Wildlife Refuge, to the east, gets more popular attention—Congress in 2017 voted to open the coastal plain there to oil leasing, a hugely controversial move that will likely end up in court—the less-known petroleum reserve is particularly choice ground for birds.

“It is more important, there are more birds, of higher density, in the NPR-A than in the Arctic Refuge,” said Rebecca McGuire, the Arctic Beringia Avian Ecologist for WCS, a nongovernmental group that performs research to inform conservation and management decisions.

The area around Teshekpuk Lake, where we had just landed, is perhaps the most important of all. Though this area covers just 18 percent of the reserve, it is home to more than 40 percent of all the aquatic birds that visit Alaska’s North Slope, government scientists reported in a 2013 study.

The far north is particularly valuable to shorebirds like that red phalarope. For a few months each year, Alaska hosts roughly 30 percent of the world’s 100 million breeding shorebirds, in the highest densities found anywhere. The North Slope alone is home to about six million of them.

View Images A pomarine jaeger flys low over its nest on the low tundra. Photograph by Kiliii Yüyan

The birds that surrounded Robards and Detwiler would disperse soon to spend the winter all over the world. Their journeys are astounding. The red phalarope will winter at sea in the Pacific Ocean off Central America. The American golden-plover will fly east across Canada, then down to South America. The bar-tailed godwit, after leaving here, will stop off in the Yukon Delta to refuel, then fly 7,000 miles to New Zealand for the winter, the longest nonstop bird migration in the world.

That’s why in 2017 an international group, the East Asian-Australasian Flyway Partnership, comprised of countries and non-governmental groups, recognized 53,000 acres around where Robards and Detwiler now walked as having crucial value to the East Asian-Australasian Flyway, which includes migrations from Alaska to east, central, and southeast Asia, Australia, and New Zealand.

The area, which had been named Qupaluk (“small bird” in the Inupiaq language), is used by at least 30,000 migratory birds—mostly shorebirds, by one rough estimate. That estimate is likely low, scientists say. The designation by the group comes with no added protections in the U.S., however.

View Images Migrating spectacled eiders feed at a tundra pond in Prudhoe Bay. Photograph by Kiliii Yüyan

And shorebirds are in trouble. More than 60 percent of North America’s shorebird populations—and nearly half worldwide—are in decline. Eighty-eight percent of the species on the East Asian-Australasian Flyway are enduring long-term population declines, McGuire said.

Humans have done this: pollution, destruction of habitat, encouragement of predators, climate change. Most of that pummeling currently happens far away from the Arctic. But as shorebirds feel the squeeze elsewhere, the prime habitat in the petroleum reserve becomes even more important, Robards said as we trooped across the tundra on another afternoon.

“Up here, if they can have a place to come breed and reproduce well, it gives us some time to figure out these other things” around the world, and improve conditions elsewhere, he said.

But, he added, “If you keep cutting them up, we’ll get to that point where the North Slope isn’t supporting these big populations anymore.”

Plans to drill

In the last few years a series of major oil finds both in and around NPR-A have focused more attention on the reserve’s sizable oil and gas deposits, in particular around Teshekpuk Lake. The geologic formations of the western Arctic are now estimated to harbor 8.7 billion barrels of recoverable oil, and 25 trillion cubic feet of natural gas, according to a 2017 estimate by the U.S. Geological Survey. ConocoPhillips has been lobbying for more access to currently off-limit areas around Teshekpuk.

View Images A female snowy owl lands at its nest as its mate watches, holding a lemming captured for its nestlings. Photograph by Kiliii Yüyan

“There are dozens of likely oil accumulations in that entire area,” said David Houseknecht, a USGS supervisory research geologist and expert in the North Slope’s geology.

ConocoPhillips has said publicly that it thinks the “special area” around Teshekpuk should be retained, but reduced in size. Modern drilling can be done responsibly, to protect wildlife and the people who depend on it, the company claims.

Another development to the north also worries Robards and McGuire. In 2016 a smaller energy company, Caelus Energy, said it had made an enormous oil discovery in Smith Bay, in state waters just one mile offshore of NPR-A. But the oil isn’t close to existing infrastructure. Tapping it would require either a pipeline under the Chukchi Sea, with its risk of a devastating spill, or else a disruptive pipeline on land, close to, or through, Qupaluk.

The impacts of energy development on wildlife populations are not straightforward. On the one hand, McGuire said, years of studying nests around the oil pads of Prudhoe Bay had not found a big impact on the ability of shorebirds to successfully hatch young. But development can affect bird populations in other ways, she said.

For instance, road construction changes the hydrology of the tundra. Red foxes, which love to eat bird eggs and which are pushing out arctic foxes on the North Slope, tend to follow roads. Other egg-eaters, including glaucous gulls and ravens, also seem to follow development. McGuire’s work also has found that as long as a decade after drilling sites have been shuttered and returned to nature, the sites are still not used nearly as much for nesting by breeding birds as sites before they were disturbed.

But the scale of development also matters. “If they put a network or road and platforms across the NPR-A, it will have an impact,” she said.

Development could arrive at a time when climate change is already altering this land. The weather is more variable. The soggy tundra that many of these birds rely on is predicted to dry out. A 2016 study in Global Change Biology predicted that about 80 percent of bird species that breed in the Arctic will see the habitat that’s suitable to them, climatically speaking, shrink by more than half. And five species may have no place to go at all, because they are at the limit of their habitat. This accretion of small pressures can add up, McGuire said. That’s why untouched places like Qupaluk, with lots of room, are important.

Most days as we walked the tundra, caribou eyed us from the distance, suspicious but also curious. The area around the eponymous lake is home to the 58,000-animal Teshekpuk herd. These High Arctic caribou don’t migrate huge distances like some of their brethren; they move around the lake throughout the year, bulking up on grasses in summer for brutal winter to come. They live on the edge, literally and metaphorically. Subsistence hunters from towns such as Nuiqsut and Utqiagvik (formerly Barrow) kill as many as 4,000 animals annually for food.

View Images An Arctic loon shakes water off its back in the midnight sun of the Alaskan summer. Photograph by Kiliii Yüyan

Researchers aren’t sure what would happen to the caribou if significant energy development such as a pipeline appeared in their habitat. Pregnant females, and those with calves, are known to go out of their way to avoid development.

“I think that initially you’re going to see some very strong responses,” said Lincoln Parrett, regional research coordinator for the Alaska Department of Fish and Game. Could these animals, faithful to an area, grow comfortable with pads or pipelines? “I don’t know,” he said. Pregnant females, and those with calves, shun development. Others have grown more accustomed to it.

Robards said it wasn’t fully understood how birds use this area, also how it will change, and exactly which areas they may need as it does. Clearly some spaces are less used than others, and could be more appropriate for development. But we haven’t figured out where those are, he said.

“Can you imagine if they put a pipeline right through where we walked this morning?” Robards said after one long walk. “There were tons of birds—include two threatened species,” he said, referring to the Steller’s eiders and spectacled eiders we saw.

If the government changes the rules for the amount of development that’s allowed here without first doing the careful work to understand the place, or at least erring on the side of caution with these animals, he said, “You’re just being reckless.”

View Images Caribou graze near an oil pipeline outside of Prudhoe Bay. Although the pipelines are raised and are technically crossable, caribou tend to change their migration patterns around these immense obstacles. Photograph by Kiliii Yüyan

In the Trump administration’s rush for what it calls “energy dominance,” though, there is skepticism that the right caution will be taken. Earlier this year, five environmental groups along with the tribal government of Nuiqsut, a native village within NPR-A’s eastern border that is now nearly surrounded by energy development, challenged in federal court the lands agency that oversees the reserve.

The lawsuit alleges that the Bureau of Land Management approved a significant expansion of energy exploration in and around the Teshekpuk Lake Special Area and around the village—nearly 70 miles of ice roads, and numerous new exploratory wells and other work—without first undertaking the required environmental studies. Some village leaders claim that energy development already is affecting caribou and other wildlife that they rely on.

Despite the scientists’ concerns about Smith Bay, David Houseknecht, a supervisory research geologist and expert on Alaskan oil deposits for USGS, said that development may not be imminent.

“It’s very unlikely there would be any development there in the very near future,” he said.

The oil reservoir has shown itself to be logistically challenging to develop, he said. He predicted that, if the management plan for the reserve is changed, the first developments would likely occur just to the south of the lake.

During our stay, Robards and Detwiler counted 35 species of birds. We also saw Arctic fox, lemmings, a grizzly bear, a snowy owl nest full of pink and white chicks. There aren’t a lot of places like this left, Robards said before the floatplane arrived and took us away. It is still vibrant, healthy, whole.

View Images An oil pipeline intersects an access road outside of Prudhoe Bay. Pipelines and roads in this wetland region bring predators to nesting migratory birds. Photograph by Kiliii Yüyan

“It’s a fully functioning system,” he said.

Christopher Solomon is recipient of a National Geographic Explorer Grant and is a 2019 Alicia Patterson Foundation fellow focusing on energy development in the Alaskan Arctic.