Tracking the Common Loon on Tomahawk Lake in Northern Wisconsin
Despite its name, there’s nothing ordinary about the common loon. For starters, it’s an ancient species – with a wingspan of five feet, and it’s related to the penguin. It’s the only loon nesting in northern Wisconsin.
The species has made a comeback here, with the population growing from 2,400 in the 1980s, to 4,000 today. Yet scientists worry about shrinking habitat and other threats. They consider it a sentinel of wildlife, navigating sometime teetering habitats.
For nearly 40 years, “LoonWatch”- based at Northland College in Ashland, has rallied citizen scientists to monitor the common loon population in Wisconsin.
Judith and John Bloom are among 350 volunteers who religiously monitor loon activity. Judith vividly remembers the first time she experienced the loon’s haunting call.
“It was 1969 in Algonquin Park in Ontario and I remember hearing them,” Bloom says.
John Bloom is navigating the couple’s sturdy fishing boat. Once a week, like clockwork, the Blooms – along with their dog Belle – survey the 3400 meandering aquatic acres of Tomahawk Lake.
This is a windy morning; not the conditions under which they normally work. Judith says they perform their 3 ½ hour ritual in calmer waters.
“We start of and go that way and we have a route we take the same time every time, because one of problems with counting is you’re trying to count the territorial pairs, but you’re also the “floaters” ; the extra loons who aren’t with a mate, and are just hanging out and I don’t want to double count any,” Bloom says.
This year six pairs populate Tomahawk. Four of them nested. The Bloom’s monitoring season starts with the loon’s arrival – as soon as the ice goes out.
“So that you can see how many nest attempts they make, as opposed to coming out in July and seeing the chick already hatched,” Bloom says.
Judith does more than counting, she has helped scientists tag birds, by slipping colorful plastic bands around their legs. She says that’s always done soon after the chicks are born. It’s the only time adult loons will not fly away.
“So you go out at night and band them right in the boat, but more often than not, he retrieves them, takes them back to shore, does his work on shore and takes them back,” Bloom says.
Volunteers have helped researchers discover a lot about loons – including their unique personalities.
“Some of them are very friendly and happy to have you right by them; others are skittish and they’ll dive – they’ll try to elude you; it depends on the bird. We try not to get too close,” Bloom says.
Judith attempts to remain dispassionate, but a sense of ownership slips out when she describes the loon pair whose territory lies closest to the Bloom’s shoreline home.
“Our pair – it’s the same male since 2008 and the female is the same for about the last four or five years. And that male, interesting enough, was hatched about 10 miles from here on Lake Mildred,” Bloom says.
There are threats to the Common Loon’s survival – including humans, whose living and playing on lakes encroaches on habitat. Loons are subject to contaminant exposure and disease. And this spring, a black fly infestation prevented many from hatching chicks.
John Bloom wants to show me a successful breeding pair. So he navigates toward calmer waters and a minute island. Judith calls it a prized nest site.
“Because the eagles can’t get at that nest, so we’re now going to literally sweep this territory to find the chick for you,” Bloom says.
An hour-long search ensues. We are wave-splashed and on the verge of giving up, when suddenly we hear a loon call; then spot an eagle high above in a towering white pine. The majestic creature tops the loon predator list.
Judith scans the horizon. A look of concern crosses her face, “I hope they haven’t got the chick.”
Suddenly she spots the second adult loon and then a ball of downy fluff. Judith watches, giddy with discovery, as the chick – little over two pounds of loon – dives. When it surfaces, an adult serves the chick a bit of fish.
All told, Judith says, the loon family will consume up to 400 pounds of fish this summer. That’s one of the reasons they are territorial; the loons need a steady, easily accessible, food source.
Judith is transfixed watching the adult deliver more fish to its chick. She scribbles notes in her log before we reluctantly swing back toward the dock. .
The common loon’s ritual nesting on northern Wisconsin lakes – their elusive presence and haunting calls across their waters – have come to symbolize wilderness and nature for many.
Conservationists hope that “human to loon” connection will help foster air and water policy to protect aquatic habitats on which ecosystems and layers of species depend.
Loon rangers Judith and John Bloom’s attention remains riveted on their habitat. They’ll continue cruising Tomahawk Lake until autumn, when – first the parents, then their young, migrate south. The Blooms will pick up their log and binoculars again early next spring as a new nesting cycle begins.