Where Have All the Loons Gone?

Dr. Walter Piper trolls silently across Whitefish Lake’s placid, moonlit surface. He spots the silhouette of a loon. A team member shines a spotlight on the bird to confuse it while Piper leans over the bow and deftly scoops it up with a musky net.

“It’s thrilling,” says Piper. He’s video calling from a Walmart in Baxter the next morning, slightly haggard from the nocturnal schedule. “It seems implausible that you could catch a loon. They’re diving—how is that going to happen? But adult loons get very protective of their chicks, and you can creep right up to them. They’re not going to leave their side.”

“I’m concerned that this is not just a Wisconsin thing. Minnesota has three times as many loons as Wisconsin. You guys love your loons, and it would be a shame to lose them.”

– Dr. Walter Piper

Piper has spent the last 30 years studying these majestic, solitary birds in Wisconsin. His decades of research have focused mostly on territorial and breeding behavior, including effects of aging in loons: where they choose to nest and why, throughout their 20- or even 30-year lives.

“It’s almost like Jane Goodall and her chimpanzees,” Piper says. “Loons are long-lived. Their life history is fascinating.”

But research priorities shifted when Piper discovered that northeast Wisconsin’s population had declined. He wants to know what’s causing the slump. Now he’s in Minnesota, partnering with Crosslake’s newly minted National Loon Center on a banded loon study. The research investigates  if Minnesota’s population is taking a similar hit—and if climate change is driving the decline.

“From my standpoint as a scientist, I’m concerned that this is not just a Wisconsin thing,” Piper says. “Minnesota has three times as many loons as Wisconsin. You guys love your loons, and it would be a shame to lose them. So, we’re trying to figure out—in a rigorous way, with marked birds—what’s going on.”

So far, Piper and his team have banded more than 170 loons on the Whitefish Chain and surrounding north-central Minnesota lakes. They’ll recapture them each summer (a process that doesn’t harm the birds, Piper assures) and gather data. And what the research shows could have serious implications for loon populations across the Upper Midwest.

And, while he suspects climate change, it’s not simply a case of warming temps driving the birds north. The first culprit, he surmises, is black flies. In small numbers, they’re simple pests. But heavy rainfalls—which are increasing with climate change in the Midwest—cause black fly populations to spike. They swarm loons, driving them off their nests.

Piper’s second suspicion? Murky water. Loons are divers: They need clear water to spot fish, crayfish, and other favorite meals. Water clarity is, in fact, a predictor of body mass for male loons and chicks. But heavy rainfalls wash nutrients from soil and treated lawns into the water, causing algae growth.

Each time his team catches a loon, they weigh it. They’ll do this every summer and compare the numbers to satellite data on water clarity. They incorporate other statistics—including survival rate and reproductive success—into a population model, which will give them a number: lambda.

“Lambda is the holy grail of what we’re trying to estimate,” says Piper. “In Wisconsin, two years ago, we estimated that lambda is 0.94, which is a terrible number. It means a 6 percent annual decline.”

There’s some prior data tracking loon populations in Minnesota. DNR scientist Krista Larson has run a citizen scientist program since 1994 that suggests loon numbers are relatively stable. But Piper argues that data doesn’t lend itself to thorough statistical analysis. He hopes his research will provide a bigger picture.

In the meantime, the National Loon Center—whose ultimate mission is to conserve our state bird—hosts educational boat tours, mostly in the summertime, where visitors can identify Piper’s banded loons and learn about the research. By 2024, it will open an immersive visitor center near Crosslake.

Piper, for his part, will continue posting updates on his website, The Loon Project. His blog is an account of a loon researcher’s peculiar life (“My hands bear dozens of small nicks and cuts—this one from the Nelson Lake female, this one from the Pelican-Breezy Point chick,” an August 5 entry reads) and a  study of a beloved species under threat. Ultimately, the research will show if loons are the regal canaries in a coal mine Piper suspects.

“I try to be optimistic, but I certainly worry a lot,” says Piper. “If you’re hoping that loons are immune from climate change, it’s getting harder to maintain that view.”

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