Standing in a thick patch of pine and fir, mosquitoes swarming her face, Anna Ortega lifted a radio receiver into the air, angling it back and forth as she listened for the blip, blip, blip of a mule deer collar. A zoology graduate student at the University of Wyoming, Ortega was tracking Deer 255, a doe that had braved road crossings, fences, wolves and other hazards to get here. Somewhere in this forest near Island Park, Idaho, a dozen miles west of Yellowstone National Park, Deer 255 was laying over for the summer.
Armed with bear spray, binoculars and datasheets, Ortega and two field assistants followed the blips among trees dappled with early July sun. They picked their way through knee-high grass and shrubs, the occasional snap of a twig underfoot as startling as a slamming door. The blips were strong and clear: Deer 255 was close. Ortega knelt, peered through a spotting scope and silently waved the rest of us closer. “I think I see a fawn bedded down,” she whispered, smiling.
Later, Ortega and her crew planned to collect samples of plants that mule deer like to eat so they could compare Deer 255’s destination to other summer ranges. But only after they found the doe herself. Ortega pointed to a fawn-shaped slash of tan among the tree trunks. We trained our binoculars and cameras in that direction, and — “false alarm,” Ortega murmured, as the contours of a fallen log became clear. She switched on the radio receiver, lofted it, and followed the blips deeper into the woods.
While not all mule deer migrate, some travel a hundred miles or more between their summer and winter ranges. With a one-way migration of 242 miles, Deer 255 holds the record for the longest-documented land migration in the Lower 48, traveling even farther than her herd-mates, all of which winter in the Red Desert of southwest Wyoming. Her trek to Idaho from the Red Desert exemplifies the surprises scientists are still encountering with this well-studied ungulate. And as mule deer populations throughout the West remain below target levels, it underscores the need to protect the wide tracts of landscape that sustain migrating wildlife.
Researchers first collared Deer 255 in March 2016. That spring, they noted her propensity for long-distance travel, but they weren’t sure whether she was making a true migration, which requires a round trip. They waited for autumn to see if the doe, nicknamed Island Park Girl, would return to Wyoming. But in early August, her collar malfunctioned. When Ortega’s colleagues asked where the adventurous deer was, she had to tell them she didn’t know; she wasn’t even sure if Deer 255 was still alive.
Then, this year, early in the afternoon on a sunny March day, Ortega and her field crew were studying Deer 255’s herd in the Red Desert outside Superior, Wyoming. Deer were netted from a helicopter, then ferried to the researchers, who collected samples before releasing them. A deer wearing a collar with a broken GPS was captured, and, because she had memorized its identification frequency, Ortega recognized Deer 255. It had been nearly a year and a half since the doe was last located. “Everyone was crowding around and just so excited to see that this was Island Park Girl,” Ortega told me later.
Deer 255 was pregnant, with twins. She had made a round-trip migration nearly 100 miles longer, each way, than the longest recorded migrations of her herd-mates, some of which hadn’t migrated at all. But why?
Ortega and her colleagues don’t know, but they do know that deer from the same herd often split up and head to different summer ranges, typically returning year after year to the same spot. Ortega explains this as a diversified stock portfolio for the herd: If catastrophe befalls one route or destination, others can ensure the group’s overall success. Deer 255’s migration “adds just a little more complexity to it all,” Ortega said. “This is another massive movement that we can add to our knowledge of migrations across the American West.”
Deer 255 is part of a well-studied group. Wyoming is a good place to research mule deer movement, says Matthew Kauffman, the director of the Wyoming Migration Initiative and Ortega’s doctoral advisor at the University of Wyoming. Partly that’s because the state’s varied landscape — from the high desert scrub of the Red Desert to the foothills of mountain ranges like the Wind Rivers and the Gros Ventres — means migration is a particularly fruitful strategy, allowing animals to follow green-up in the spring and escape the harshest extremes of both winter and summer. “These animals have figured out these solutions of how to have the best of both worlds and how to sort of stitch it all together with the seasons,” Kauffman says. “To me, that’s the exciting part of 255. She’s showing us yet another way to make a living on this landscape.” There’s a broader significance to her journey, too, he told me. “Here we are in 2018, and big game species like mule deer and elk are some of the best-studied animals on the plant. And yet, we’re still discovering these sort of secret ways they have of exploiting these landscapes.”
Humans, of course, are exploiting the very same places. Fences, roads and development — both urban growth and energy expansion — all infringe on mule deer habitat and migration corridors. In 2016, the most recent year for which information is available, officials estimate Wyoming’s mule deer population was about 396,000, about 28 percent below the target population. Still, the state has seen modest improvements in fawn survival and population increases since 2014, says Daryl Lutz, the Lander region wildlife management coordinator for the Wyoming Game and Fish Department. That’s thanks to well-timed spring and summer rain, which nourish the plants mule deer eat. On-the-ground improvements like retrofitted fences and protected habitat likely played a role, too. “I guess we’ll wait and see how long we get to ride this wave,” Lutz says, “but we’re hopeful.”
And while mule deer are an iconic feature of Western ecology, they’re also important economically. In 2016, between hunting license and application fees, conservation stamps and other sources, Wyoming brought in more than $15 million to manage its mule deer program, a sum that doesn’t include the additional money hunters and wildlife watchers spent on gas, motel rooms, guides and other goods and services.
But that economic windfall is dwarfed by another source of revenue: fossil fuel development. According to the think tank Resources for the Future, oil and gas brought Wyoming about $1.8 billion in 2013. Research shows that building well pads and roads, drilling, and maintaining energy infrastructure is disruptive to mule deer. In one 17-year study, scientists from the University of Wyoming and Western Ecosystems Technology, an environmental consulting firm, found that deer never became habituated to the presence of natural gas wells, despite restoration efforts. The number of deer wintering in the affected area dropped by more than a third — even as hunting declined over the same period.
That makes for potentially competing goals for the Interior Department. It must follow President Donald Trump’s explicit prioritization of energy development on public land. And it must adhere to an initiative announced earlier this year by Interior Secretary Ryan Zinke to work with Western states to improve habitat for mule deer, elk and pronghorn, including migration corridors. Given Zinke’s energy-boosting track record, it’s unclear which priority will prevail.
From Zinke’s point of view, however, “it’s not an either-or,” says Casey Stemler, the Fish and Wildlife employee leading the order’s implementation. Federal efforts, while allowing for oil and gas drilling, will follow state priorities for habitat protections. That’s what happened in late July, when the Interior Department deferred oil and gas leases on three parcels that overlap with the migration route of Deer 255 and her herd, and restricted development on several others; the Wyoming Game and Fish Department had requested those changes in a June 5 letter to the Bureau of Land Management.
But the Interior Department’s actions don’t go far enough to protect mule deer, says Julia Stuble, a Wyoming-based public land and energy expert for The Wilderness Society. “They are coming under the cover of saying, ‘Well, it’s what the state wanted,’ (but) they can do plenty more,” Stuble told me. “If they can defer three parcels, they can defer all of them.”
Back on Deer 255’s summer range, Ortega led us deeper into the forest, her skin now dotted with blood and welts left by mosquitoes. In a small clearing, she dropped behind a rotting log and, throwing her hands above her head, motioned to the rest of us in victory — or perhaps frustration. As we hurried over, mindful of cracking twigs, she whispered that she’d gotten a good look at Deer 255’s distinctive collar, but the doe had spooked. In low, quiet voices, we were discussing our next move — should we circle around and try for another look? give up and collect the plant samples? — when one of the assistants, gazing into the woods, murmured: “I see her.”
A swatch of tawny fur flashed through the evergreens, and then it was gone. We grinned at each other, muffling our excitement, until Ortega and her assistants turned to more mundane measurements. They began identifying plants and collecting samples — sticky geranium, heart-leaf arnica — studying the destination that Deer 255 had traveled so far to reach. “I feel like I would be missing a part of the story to not be actually on the ground looking at her summer range,” Ortega said, no longer whispering. “It was great to get a fleeting glimpse of her. She remains elusive to us, but that’s OK.”