Thousands of nesting birds have vanished at Great Salt Lake’s Gunnison Island

Flocks of pelicans and gulls that once darkened the sky have disappeared, and scientists say land bridges from persistent low water levels are likely to blame.

Al Hartmann | The Salt Lake Tribune Utah Division of Wildlife Rescources, University of Utah and Westminster College scientists visit Gunnison Island in the northwest corner of the Great Salt Lake to install trail cameras in 2017.

Thousands of American white pelicans fly into Gunnison Island each spring to nest and raise chicks. But this year, there are almost none.

The pelicans choose the site due to its isolation in the north arm of the Great Salt Lake. There is no fresh water. There is no shade. There is almost no food. And until recently, there also weren’t any predators or people. Pelicans value their privacy so much they are willing to brave the harsh conditions, leaving their vulnerable offspring unguarded each day while they fly several miles to gather the fish needed to feed them.

Gunnison Island is located in the north arm of the Great Salt Lake. A rock-filled railroad causeway has essentially cut the lake in two and cut off the north arm from fresh sources of water, which is why it’s a different color.

The Great Salt Lake’s receding water, however, has created land bridges that allow access for sharp-toothed scavengers and human trespassers. Since at least 2017, the access has put one of the nation’s largest nesting pelican colonies at risk. That’s when trail cameras detected a coyote exploring the island.

This year, state wildlife managers canceled a juvenile banding trip after an initial plane survey found far fewer birds than ever observed before.

“It doesn’t look like it’s worthwhile to band,” Great Salt Lake Ecosystem Program Manager John Luft said in an interview Thursday. “We flew over this morning. It was pretty dismal out there.”

The dire situation at Gunnison Island might come as a surprise. Sailors and state resource managers celebrated this spring as a record-breaking, phenomenal snowpack raised the lake more than five feet from the record low it sunk to late last year.

But that’s only half the story.

In order to manage the shrinking lake’s spiking salinity, regulators have raised the rock-filled railroad causeway berm bisecting it, effectively cutting off the north arm, where Gunnison Island lies, from any new inflows.

Although rising water in the south means some new water is spilling over the causeway again, the north half has only risen one foot higher than its recorded low.

The north arm’s water will have to rise five feet more for Gunnison to become an island again.

“Why bother to nest there if all your young are going to be eaten up?” said Lynn de Freitas, executive director of Friends of Great Salt Lake. “[We need to be] bringing the lake up as a lake, not just the south arm and the north arm as an afterthought.”

‘I expected this to happen years ago’

State biologists have consistently monitored Gunnison’s pelican colony since the 1980s. In 2011, they began boating to the island to band the flock’s fledgling chicks, toiling in the summer heat to corral, wrangle and tag the birds in an effort to better understand their migration and population health.

They only have a small window to do their grueling work — if the parent birds fly back in from fishing at Bear Lake or Bear River Bay and see a bunch of scientists messing around their home, they’ll completely abandon it along with their young.

As the Great Salt Lake receded to alarming lows, scientists started taking ATVs to the island instead of boats. They also installed trail cameras around the island in 2017, suspecting intruders had ventured across the drying lakebed.

PeliCam photos courtesy of Great Salt Lake Institute at Westminster University and the Utah State Division of Wildlife.

Those fears were quickly confirmed when the equipment captured an image of a coyote.

“I can’t imagine they would eat all the pelicans,” said Bonnie Baxter, who directs Westminster College’s Great Salt Lake Institute and helped install the cameras, “but what happens is they cause disturbances.”

Scientists have tagged as many as 500 birds on their Gunnison Island banding expeditions. In 2019, they only managed to get 74. They haven’t made it to the island to check on the juvenile birds since. The COVID-19 pandemic shut down their fieldwork in 2020 and 2021. Avian flu prevented them from venturing to Gunnison in 2022.

Still, what they are observing from above is a stark contrast to what Captain Howard Stansbury described when his barge docked at the island during his Great Salt Lake survey of 1850.

“They literally darkened the air as they rose upon the wing,” Stansbury wrote of the pelicans and gulls. “... The ground was thickly strewn with their nests, of which there must have been some thousands.”

PeliCam photos courtesy of Great Salt Lake Institute at Westminster University and the Utah State Division of Wildlife.

Modern observations have found up to 20,000 breeding pelicans visiting Gunnison Island each spring and summer. They still lay their eggs directly on the ground, spreading out across the site’s many bays and beaches.

This spring, however, Luft and his team only saw about 5,000 adult birds, but they appear to be abandoning their nests in droves and they have been amassing on the island’s northern tip instead of occupying all corners. As of last week, Luft said, there were fewer than 1,000 adults. As of Thursday, there are virtually none. All the state biologists observed were a few dozen juvenile birds, too young to fly, hiding in some rock outcroppings.

“I expected this to happen years ago,” Luft said, “and it finally has.”

They haven’t been able to regularly check on the trail cameras either, but researchers with the Great Salt Lake Institute have confirmed there is at least one pair of coyotes and one pair of foxes who have taken up residence at Gunnison Island.

“It sounds like ... the reasons why they chose that island,” said Carly Biedul, the institute’s coordinator, “those reasons aren’t there anymore, [including] the isolation.”

And pelicans are not the only birds that rely on Gunnison Island to nest. It sees tens of thousands of gulls each year, which have also gone missing according to Luft.

“That’s unusual,” he said.

Some great blue heron also raise their babies on Gunnison, at a nest they may have used for more than a century, Baxter said. In 2019, their cameras caught a coyote striding toward it, staring down a helpless chick.

“It’s so sad,” Baxter said.

The scientists said they are not entirely sure just a handful of coyotes and foxes have caused Gunnison’s nesting colonies to collapse. There could be more than they realize. Or avian flu could possibly play a role. They will need to do more study to be sure.

Still, de Freitas with Friends of Great Salt Lake said the loss of nesting birds on the island points to the need for a lake-wide target elevation — an idea lawmakers rejected earlier this year. The Division of Forestry, Fire and State Lands created a matrix for the lake that shows an elevation of around 4,200 feet above sea level is the most sustainable for recreation, industry, islands and migrating birds.

The lake currently hovers at about 4,194 feet in the south and 4,189 feet in the north.

“Without a target elevation,” de Freitas said, “you don’t know what you’re doing. It’s hit and miss.”

This article is published through The Great Salt Lake Collaborative: A Solutions Journalism Initiative, a partnership of news, education and media organizations that aims to inform readers about the Great Salt Lake.