Aug 29, 2013 — Loons have enjoyed unprecedented population growth over the last 30 years. They outlived DDT and a time when people used to shoot loons for sport.

In the new issue of Adirondack Life on newsstands now, David Sommerstein has an article on how a study of loons finds that things could have been even better. The culprit is mercury pollution. Last summer, David joined researchers banding loons in the middle of the night near Old Forge and filed this story.

It's the middle of the night, and I'm with some researchers banding loons near Old Forge. I like loons. I'm sure you do, too. When you hear their call echo across the water, you feel special.

But it's a totally different feeling when you're in a boat, someone swoops a net into First Lake, scoops up a loon chick, and plops the amazingly tiny creature into your lap. That's what happens to me.

Nina Schoch, who runs the Biodiversity Research Institute's Adirondack Center for Loon Conservation, says the chicks are kind of like owls: "they like to have their heads rubbed and it will put them to sleep and keep them calm."

Her team has banded and monitored more 200 loons in the Park since 1998. This one struggles to get away, so I pet its grey down, soft like a kitten's, and it quiets.

Tonight, we're trying to catch adult loons to put geolocators on them, so they can be tracked year-round. The loon chick is kind of a hostage, to lure in its parents. Five of us are in a DEC motorboat, bundled up in raincoats and winter hats.

Banding loons is really a labor of love. Labor because you have to do it at night. It can get cold and rainy, even in summer. The loons don't want to be caught. So you trick them. You play an electronic call to lure them close, shine a floodlight in their eyes to blind them, and, Schoch says, you still might miss.

[pullquote:right]"It's almost magical being out with them, but it is very frustrating when they come so close to the boat and you think you have them in the net and the net comes up empty."

The love, of course, is why these researchers have dedicated large chunks of their lives to the iconic birds.

Loon sentinel Gary Lee holds the net like a staff and scans the water's surface. Between whistles and calls, he tells me he talks to all his birds, "I watch 22 lakes and I talk to all the birds. I go in the same canoe every time, same clothes. They know me. They talk to me when I go out there."

Lee and Schoch worry about loons like parents, even though the birds are thriving these days. Lee says he saw kids on jet-skis buzzing loons. One loon on this lake has a broken leg from a motorboat. Lead sinkers and other fishing tackle are poisoning birds.

But Nina Schoch says the biggest threat is mercury: "21 percent of the males and eight percent of the females have mercury levels high enough to impact their reproductive success."

Schoch and her team observed those high mercury birds, and what they saw alarmed them.

"Mercury is a neurotoxin, so it makes them depressed and lethargic and they don't have the energy to defend their territories well, they don't get up on the nests as much. They just don't have the energy like they normally would to care for the nest and the chicks."

A study released in 2011 uses Schoch's data to quantify the effects of mercury.  It found male loons with high levels of mercury in their blood produce 56 percent fewer chicks than healthy loons, and female loons 32 percent fewer.

Study co-author David Evers says mercury is dampening the overall good news of the loon's rebound over the last three decades.

"So there's a recovery going on now across the region, but it would have been stronger recovery, and I still wonder will that recovery continue if mercury is a stressor. What happens when other stressors come into play?"

Evers says the implications go beyond loons. They're a good indicator species, because they eat at the top of the food chain and live up to 30 years.

"If it's affecting loons, it's affecting other birds that are eating fish regularly from those same lakes, and I think you can easily make that next step that that can impact our own health, especially if we're regularly catching and eating fish from those same lakes."

The mercury comes predominantly from coal-fired power plants in the Midwest. Clarkson University professor Tom Holsen has been studying mercury in the Adirondacks for more than a decade.

"Prevailing winds, as we all know who live here, are from the southwest, and that's the exact direction of the coal-fired power plants."

In 2011, the Environmental Protection Agency finalized new rules for mercury emissions. And already dozens of coal-fired units are being shut down because they're too costly to retrofit. Utilities say that will mean higher electricity prices. But Holsen says it should also lower mercury levels in Adirondack lakes.

Now attention is turning to global mercury levels as coal continues to power Asia's economies.

***

Back on First Lake, it's around midnight. I've been petting the loon chick on my lap for half an hour. Finally we catch an adult.

It's a loon they've never caught before. Gary Lee wrestles it into his arms and tucks its bill behind his back, as the bird chews on his pocket and fights to get away. "I mean, she's trying to swim on my lap."

Schoch takes all kinds of measurements and samples, then she straps the geolocator on one leg and an ID band on the other. Then we let the loon and the baby go. Schoch and Lee drop into their seats and take a deep breath.

There's lots of good news in this story: the number of breeding loon pairs in the Adirondacks is estimated to have doubled since the 1980s. And stricter rules appear likely to reduce mercury contamination in the Park.

Still, researcher David Evers argues concern for loons and funding for more study has to continue.

"We have reversed the tide that has happened a century ago. That's a great thing that we should be happy about. I think we can do more. And I think some things like mercury get in the way."