Mule Deer Populations are on the decline

Mule deer populations are declining across the West. In Central Oregon this decline has been attributed, in large part, to habitat loss due to human developments. 

Research seeks reasons for demise of mule deer

Published on WyoFile by Angus M. Thuermer Jr. | JANUARY 20, 2015  

LaBarge — Pilot Mark Shelton swoops the Robinson R44 helicopter to hover near an oil well, gently setting down bagged, blindfolded and trussed-up mule deer No. 42 that’s dangling below the airship.

Eight researchers rush to gather the doe and another female that Shelton and his net-gunner have just caught. The ground team will measure, weigh and take samples from the two does for one of five western-Wyoming mule deer studies.

“She’s a pretty small gal,” Carhartt and wool-clad graduate researcher Samantha Dwinnell says after reviewing 42’s measurements. Five feet, five inches from nose to tail, 120 pounds.

There’s a lot more Dwinnell and her colleagues know about this mother because they’ve caught her before. She had a fawn this year, twins the year before.

At six-and-a-half years old, her body fat amounts to 9 percent of her weight. She summered on the upper Smith’s Fork, migrated 43 miles, swam the Green River to get here.

She has a 39-inch chest, a 14-inch metatarsus – the lower part of her back leg. She’s fat and sassy, struggling occasionally against her bonds.

Along with other does that roam the forested mountains and sage hills from Star Valley to Kemmerer, she’s the hope of a troubled 33,000-member herd. Gathering their stories, Dwinnell and others at the University of Wyoming Cooperative Fish and Wildlife Research Unit hope to inform decision-makers how they might restore a herd that once numbered 50,000.

“Mule deer are struggling,” says Matt Kauffman, University of Wyoming professor of zoology and physiology, who with his crew, caught, wrangled and released 175 deer one week last December. “Mule deer are declining across Wyoming and the West.”

Wyoming Game and Fish Department strives for a population of 564,150 mule deer, but the last statewide estimate was 374,400, just two-thirds of objective. Biologists considered the Wyoming Range a mule deer factory, but today its herd mimics the statewide decline.

“It was an incredibly important destination for sportsmen,” Kauffman says of the Wyoming Range and the Salt River Range that rises beside it in Sublette and Lincoln counties. “Game and Fish was pushing to do a study … they’re explicitly trying to understand why Wyoming Range numbers haven’t recovered.”

To that end, the co-op team takes to the field twice a year to catch Doe 42 and about 40 other radio-collared female herd members. The Wyoming Range study is one of five the team will work on for a week. In eight days they’ll capture does from the Pinedale Mesa to the Red Desert, from Cokeville to Rock Springs.

“The major theme is mule deer and their habitats in transition,” Kauffman says. The studies focus on the impact oil and gas and other development has on wintering mule deer, how it affects their migration, and the effect of long-term drought or climate change.

Researchers also monitor what’s believed to be the second longest terrestrial migration in the Western Hemisphere. Four thousand to 5,000 mule deer travel 150 miles from the Red Desert to Hoback Junction twice a year.

“We’re really trying to tell their story, their individual stories,” says Kevin Monteith, an assistant research professor at the university. “They are the ones that are providing information.”

Matt Hayes, Melia Devivo and Teal Wyckoff haul a deer from the landing site for processing. After a helicopter team drops the does off, researchers spend about 10 minutes collecting data from each animal. (Angus M. Thuermer Jr/WyoFile — click to enlarge)

The eight days of capturing are hectic. “Dr. Monteith’s 5 AM alarm ringtone is stuck in my head,” Kauffman tweets one morning. He’s broadcasting the capture week on Twitter and Facebook.

Most of the core team of about 10 stays at a U.S. Forest Service bunkhouse in Pinedale during the first half of the week. It’s got eight bedrooms, common space, and a kitchen.

“The students” cook a spaghetti dinner one evening. When the team’s home at night, a dozen pairs of winter boots dry by the door. As bedtime approaches, Kauffman, Monteith and others work on their computers, Dwinnell collects radio collars, drugs and other supplies.

Before light the next morning, workers begin their routine, dressing warmly, swilling coffee and bolting bagels. Game and Fish wardens and other helpers join the university students and teachers at a parking-lot rendezvous.

Before the first coffee klatch assembles in Pinedale, their convoy is on the road. It takes about an hour to reach the day’s first staging location near LaBarge. On a ridge top, the team sets up a scale and mats as the sound of a helicopter grows with the dawn.

All the studies rely on catching, collaring, measuring and following mule deer. The helicopter crew catches the animals from the air with a net gun, then drops a “mugger” off to wrangle the animal into a set of hobbles and blindfold. Once trussed, the deer is laced into a bag and slung below the airship to be deposited gently near the staging and processing site.

Three of the studies catch the same set of deer twice a year; the helicopter team must seek specific animals to net. The ground team takes measurements, performs tests and gathers samples before releasing a deer to its herd and family.

Devivo and Kauffman work on a deer as other team members perform their tasks. Researchers draw blood, replace radio collars as necessary, obtain a fecal sample and other data before releasing each animal. (Angus M. Thuermer Jr/WyoFile — click to enlarge)

It takes about 10 minutes to process a deer once Shelton and mugger Donnie Wackerman deliver it. A team of four workers runs to where Shelton sets down the animal, then carries it to a processing pad.

Dwinell checks the teeth. She’ll pull one from each new deer to get an accurate age.

Love of the outdoors attracted her to this work. A University of Wyoming masters’ candidate, she graduated from the University of Minnesota in Duluth in 2007 and planted herself in the Rockies, learning mountain ethos in Victor, Idaho. Now on her fourth capture week, she’s a key organizer of the field team.

“Double check the ID,” she reminds the crew late on a cold, tiring day. “Make sure you have the capture number. None of it means anything unless it’s on the data sheet.”

Most team members are her fellow lab mates who have field experience and hustle. “We like working in those environments,” she says of the snow and cold. “Adverse weather doesn’t bother most of us. It’s sort of what we thrive on.”

When she’s checking a deer’s teeth, another team member inserts a thermometer at the animal’s far end. There’s a danger it might overheat from the stress of being captured.

“One-o-four is the threshold,” first-year masters student Alex May says of the highest tolerable temperature. “One-oh-three is when we pay attention.”

Too much heat calls for a cold-water enema.

Meantime, one team member will draw a large syringe of blood to be distributed into vials and onto blotter pads. Someone checks the radio collar and replaces it as necessary.

Another worker stretches a tape along and around the deer, then measures a back leg joint. A gloved volunteer mines for a fecal sample, sealing it in a plastic bag. In the lab, someone will find out what each doe ate.

At the rump, assistant research professor Kevin Monteith scrapes hair off a small patch of skin. He applies an ultrasound sensor to help calculate the percent of body fat. He checks for milk – it will tell whether she successfully brought a fawn or fawns to the winter range.

Brett Jesmer, a doctoral candidate in the zoology and physiology department drills deeper. When Monteith is done at his bare patch on the rump, Jesmer moves in with a numbing agent and biopsy needle.

He extracts a sample of fat and muscle for analysis. They will reveal how well she benefited from her summer’s grazing. After her condition changes over the winter and she’s caught again, he’ll know what she’s burning — fat or muscle — to survive the winter.

He swabs the biopsy site as the doe gets a shot of antibiotics before being weighed. A scribe jots down all the information.

Sam Dwinnell injects a deer before pulling a tooth, required to obtain the accurate age of each animal. Many on the capture team have specific jobs they perform as each doe is brought in for processing. (Angus M. Thuermer Jr./WyoFile — click to enlarge)

Co-op unit leader Kauffman, son of an Oregon horse logger and schoolteacher, grew up in the outdoors. Now, wandering mulies keep him bonded to those places.

“As a kid and a youngster, I’ve always enjoyed hiking and camping and mountains and wide-open spaces,” he says. “In migrations, the animals are connecting those things for you.

“I don’t typically connect to the animals on a more intimate level,” Kauffman says. Yet he knows the charisma the fuzzy species holds.

“When my 12-year-old son came out as a volunteer, he was holding the head of the animal and petting it for me.”

Monteith is different. During the week he routinely cradles a captive deer’s blindfolded head in his lap, petting it gently. One brays and kicks as he inadvertently pains it during the processing.

“Sorry sweetheart,” he says. “It’s my fault.”

The researcher’s reactions are natural, Dwinnell says. “The animal is undergoing a lot of stress. It’s sort of instinctual to give it the kind of comfort we’re used to — talking to the animal, petting the animal.”

Game and Fish warden Todd Graham, who joined the capture team for a few days, more often deals with animals that are dead or in distress. They’ve been hit by trucks, just killed by hunters. Helping researchers gives him a different experience.

“It’s not often you get to put your hands on live, healthy animals,” he says cradling a captured mule deer’s head and rubbing its neck as colleagues work on it.

Masters candidate Teal Wyckoff talks to deer too. “Although we say things, it’s for ourselves,” Wyckoff says. “In reality we are perceived as the threat.”

Among the observations recorded on each animal’s capture data sheet is a characterization of its anxiety.

“The vast majority are in that ‘calm’ category,” Wyckoff says. It’s possible that after being captured once or twice, the deer are less frightened.

“I think they actually get used to us,” she says, “but that’s not a rule.”

When the team’s digital scale, right, breaks, the group improvises, using a pole and wire warden Fralick had in the back of his pickup. The backup scale allows researchers to collect data that’s important to their work tracking individual animals’ conditions. (Angus M. Thuermer Jr./WyoFile — click to enlarge)

If researchers don’t fall for the does’ cuddly looks, they marvel after learning what it takes to raise a family in the Wyoming mountains. Monteith marvels at one old doe whose teeth are just about worn down.

She’s lactating. She’s raised another generation of mulies since he saw her last, even though she can barely chew.

“She won’t quit,” he says. “They’ll continue to produce babies and raise them as long as they’re alive. The more I learn about their world, the more respect I have for them.”

Dwinnell’s awe grows as she tracks and watches mule deer that she knows. In summer she’ll follow them across a tapestry of forests, cliffs and rivers.

“Most of them summer in real high elevations – some of them in extreme terrain,” she says.  “Some can travel a hundred-plus miles to these winter ranges where they’re exposed to these harsh environments. That’s enough to warrant a lot of respect.”

Fawn surveys are the most fun, especially those she conducts in idyllic wilderness meadows, rich with all things natural.

“It’s pretty satisfying to see them come back when they’ve raised two fawns,” she says. “It makes sense — [they] were in really awesome habitat. Scientific theories pan out the way you would expect them to.”

Deer’s long-range movements are endlessly fascinating for Kauffman and they make up an important aspect of all five studies.

“Why do they make these migrations, how do they benefit from them,” he asks. “One of the most interesting things about terrestrial migrations and things like mule deer is all the decisions they make. And you have these vast landscapes that support these movements. It forces you to think about the animals and the landscape at the same time.

“The most difficult question is how they respond when the landscape is altered,” he says. “They’re encountering more fences, running into people, roads.

“The biggest question is, in what state of wildness do these landscapes need to remain in in order for these migrations to still be incredibly beneficial strategies for these animals?”