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Biologists intervene to keep swans alive in Yellowstone

Last Updated Jul 25, 2018 at 2:21 pm EDT

In this June 6, 2018 photo, the only nesting pair of trumpeter swans in Yellowstone National Park swim around their nest on Grebe Lake just west of Canyon Village, Wyo. Grafting trumpeter swan babies into the nests of wild adults is, for now, the way things work in Yellowstone. The trumpeter population here has been on life support for seven years. (Bradly J. Boner/Jackson Hole News & Guide via AP)

JACKSON, Wyo. – A trio of sprightly two-day-old cygnets hears their new foster parents calling nearby. Instinctively, the young, captive-raised swans jump off a platform and paddle into the chilly waters of Yellowstone National Park’s Grebe Lake.

Bad move.

This is a swan “graft,” an effort to trick the two adult swans into raising the three young now swimming toward them.

But “mom” and “dad” aren’t enthused. Hovering near their man-made nest platform in the lake, the adoptive parents see the fast-approaching youngsters as pests, rather than beloved offspring. Instead of bonding, they start batting at the young.

Suddenly the cygnets are endangered by birds dozens of times their size. Making matters worse, a pair of potentially predacious loons are inching near the defenceless young.

RECOGNIZING A CRISIS

Grafting trumpeter swan babies into the nests of wild adults is, for now, the way things work in Yellowstone. The trumpeter population here has been on life support for seven years.

“At our historic high we had 65 swans in Yellowstone, and we were down to eight or nine” by 2011, Yellowstone Senior Wildlife Biologist Doug Smith said. “To be honest, we were freaking out.”

A gathering of swan experts that year didn’t provide answers, but Smith took action anyway.

National Park Service managers, who prioritize native species and natural processes, don’t take intervention lightly. But in this case, managers chose intervention over possible extirpation. Smith, best known for leading Yellowstone’s wolf program, stepped in because he believed human activity was to blame for at least some of the decline of the park’s population, an icon of trumpeter swan recovery.

At one point in the 1930s trumpeter swans had been killed off almost everywhere in the Northern Rockies but Yellowstone and the nearby Red Rock Lakes National Wildlife Refuge. Now the narrative has flipped, and Yellowstone is investigating why. The leading hypothesis is that too many of Yellowstone’s 4 million annual visitors tromp too close to the shorelines of the park’s few shallow, weedy lakes and streams, displacing swans from their best habitat.

“The areas that used to be good for swans have a lot of people visiting now,” Smith said.

The disturbance pushes trumpeter families out into the middle of lakes, away from protective vegetation and into open water where cygnets are far more vulnerable, he said.

“They get dive-bombed by a bald eagle,” Smith said, “and the bald eagle kills the chicks. I’ve seen this happen, and so has someone in my crew.”

It’s Riddle Lake — just off the main drag between Lewis Lake and West Thumb — where the eagle onslaught has been documented for the past five years. One of just two of Yellowstone’s remaining wild swan pairs nests here, and they’ve managed no better than raising a single cygnet to adulthood in recent history. This year they didn’t nest at all.

Yellowstone made a rather drastic management decision to help the birds, and for the past four years has closed the area to public access through Sept. 15.

“It was tough,” Smith said, “because Riddle Lake is one of the top day hikes in the park.”

CRISIS AVERTED, CYGNETS RESCUED

Back at Grebe Lake, 27 miles north of Riddle Lake near Canyon, the swans have at least nested.

It’s June 19, and a rainstorm the day before put the kibosh on transplanting the three recently hatched cygnets.

Because of the weather delay the young swans spent one extra day in their Wyoming Wetlands Society incubator in the basement of a Pearl Street office building before being escorted north to Grebe Lake. It was 24 hours too long, Bill Long would learn, as the precocious waterfowl grew too rambunctious by the next day.

Chaos ensued as the would-be foster parents at Grebe Lake rejected the trio as invaders. The young swans’ human guardian, Long scrambled to save the cygnets he’d put so much time, money and heart into raising.

The retired Wyoming Game and Fish Department warden drove back the loons by slapping the water with a broom. He imitated the swan parents, calling with “hoos” to draw the cygnets toward him. Eventually, he rounded up the sopping batch of birds just rejected by their host parents.

Crisis averted, but the grafting operation failed.

“We tried to graft babies that were too old,” Long said after the ordeal ended. “Timing is so critical. You have to have the cygnets stay on the nest.

“If they don’t bond,” he said — “Well, you just saw it.”

WELCOME ASSISTANCE

This year Yellowstone’s wild swans won’t raise any young, one setback in the long-term fight to keep the park’s swans from blinking out.

Mankind’s influence on the temperature of the planet may also have a role in the slow, steady decline. Climate change, Smith said, is causing cold, wet springs in Yellowstone, conditions that aren’t conducive to swan nesting. Wetlands are drying out later in the summer, he said, and there’s overall more variability in the weather.

A final hypothesis, also unproven, is that the cessation of supplemental swan feeding at Red Rock Lakes, a wintering site, has trickled down to the regional population.

Long has a decades-long history of raising swans, even dating to when he was posted as a warden near Elk Mountain — well outside of trumpeter’s range. He co-founded Wyoming Wetlands Society 32 years ago, and for the past seven years he has played a central part in Yellowstone’s efforts to keep its trumpeter swan population afloat. The Jackson-based non-profit works primarily with trumpeter swans and beavers, and is experienced raising its avian subjects in captive settings. Swan ponds in places like the South Park pasture off South Highway 89 and off High School Road are used routinely for this purpose.

The Grebe Lake nest had been failing time and again in the years leading up to the park’s 2011 intervention. Predation was one suspected cause, as was faulty genetics, but the pair’s shoreline nest was also being inundated as the lake level rose during runoff season. Long suggested building and bedding an in-water platform that would move with the lake level, and Smith signed on.

“Shockingly, next spring, they went right for it,” Smith said. “It was almost like they were desperate for it. I saw tracks in slush ice of the female walking out to it.”

But even with the platform, the Grebe Lake swans’ clutches were failing.

The wolf biologist and retired warden dialed up the human assistance, and began swiping the large, mottled eggs from the trumpeter nest in the days after they were laid.

The cygnets are then hatched in an incubator and grafted back into the nests immediately or returned to the Yellowstone wild when they were 90 or so days old and large enough to survive on their own.

EGG OPERATION

Long strapped on waders June 6 this year to recover the Grebe Lake birds’ eggs.

He grasped a broom in one hand for self-defence against protective parents that can top out at over 25 pounds, and a towel-lined 5-gallon pail to carry the eggs in the other. The first phase of the graft, recovering the eggs, went smoothly. Mom and dad swam nearby noisily hooing, but nothing more.

“It’s the last of the Mohicans, right here,” Long said back at the shore.

“Three of them,” he said. “That’s a classic number for old birds, so that’s good. None of them smell, so that’s good, too.”

Long’s gloved hand gingerly wrapped Yellowstone’s only three trumpeter eggs from 2018 into Kmart tube socks to keep the clutch warm during a deadfall-ridden 4-mile hike back to the Grebe Lake trailhead.

Once hatched, these cygnets will not return to their parents. Instead, to supplement the genetics of trumpeter swans that have navigated at least two population bottlenecks, Long will swap in Jackson Hole cygnets in their place.

The plan was to raise the wild cygnets at captive ponds and then release them in the Hayden Valley come fall.

In Jackson, Long and his Wyoming Wetlands Society colleagues know just what to do with the eggs. They’ve hatched over 700 cygnets in incubators that hover just shy of 100 degrees. Imitating mom’s natural routine, eggs are turned over and rotated 180 degrees every two hours, except during the night. They’re regularly misted with water to imitate the wet plumage from mom’s underside. That’s the task, for about a month, until the cygnets beak their way through the eggshell.

Over the years most of the cygnets haven’t been released in Yellowstone park itself, but rather along the fringes of a tristate trumpeter swan population that covers much of the larger ecosystem. Deep pockets are underwriting the restoration effort. Walter Wehtje, who directs the Ricketts Conservation Foundation, has budgeted $2.5 million over the next decade to support Long’s work.

“The partnership’s long-term goal is to, within the next 10 years or so, have produced enough swans that we can call the reintroduction program completed,” Wehtje said.

The plight of Yellowstone’s swans — a “shocking” piece of news, he said — is partially what attracted the philanthropic group.

A TURNAROUND

The 2017 nesting season was a total flop, because the big snow year kept Yellowstone’s lakes locked in ice into the nesting season. This year’s grafting attempt failed. But the technique is mostly working. Releases of fledged adolescents are also augmenting numbers. Yellowstone’s swans have turned a corner.

“We went from single digits in the population, to now we’re in the mid-20s,” Smith said. “We’ve saved them in the short-term.”

Trumpeters typically don’t breed until they’re 3 to 5 years old, which means the first Wyoming Wetlands Society birds are just now coming of age. Some have paired up and established territories, but through 7 years of intervention, eggs in new nests have not yet materialized.

“They’re a bird that teaches you patience,” Smith said. “I’m sitting here still waiting for them to form new pairs and breed. I’m like, ‘Come on man, give me a break, birds, get going.'”

The goal is to build the population up to something more sustainable.

“I’m sorry for a really bad pun, but right now all our eggs are really in two baskets,” Smith said. “I’d like to have six or eight baskets out there.”

Ending the intervention hinges partly on meeting those goals, but it also depends on what emerging science says about why the swans are struggling.

“Until we resolve these lingering questions, we’re going to stick with it,” Smith said.

This summer Yellowstone turned loose an avian biological technician, Evan Shields, to investigate the nuanced and mysterious decline. He’ll explore Yellowstone’s historic swan dataset — the most thorough of any bird species — and monitor swan breeding pairs inside and outside the park to get a better grip on conditions that lead to the swan struggles. Perhaps, Smith pondered, Yellowstone’s just a high plateau peppered with substandard swan habitat.

“Is Yellowstone all bad sites,” he said, “or is it a mix of bad and good, and there’s hope?”

SWAN COMPLICATIONS

At the Grebe Lake trailhead Long moved the cygnets he scrambled to save from the bucket into a mobile incubator. Although the clutch was rowdy and boisterous on the hike in — one even jumped ship — they’re tuckered out and silent on the hike out.

“I’m glad we salvaged them,” Long said. “It’s bad enough they didn’t graft. To lose cygnets would have been a travesty.”

Although the long-term effort to keep wild swans in Yellowstone is working, setbacks keep cropping up.

Smith and Long intended to set some fledged cygnets free later in the summer, but the three eggs Long carefully collected from Grebe Lake won’t be part of that cohort. While more than 80 per cent of the hundreds of incubated trumpeters Wyoming Wetlands Society has reared manage to hatch and survive, the Yellowstone eggs did not.

One Grebe Lake cygnet essentially suffocated in the egg while breaking free. The remaining two died three days later for unknown causes. Long is determining the cause of death, and though he’s got his hunches he’s not anticipating any straightforward answers.

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Information from: Jackson Hole (Wyo.) News And Guide, http://www.jhnewsandguide.com