A resurgence of cormorants at Leech Lake is pitting anglers against environmentalists
BEFORE DAYBREAK, a fishing boat motors across Leech Lake in northern Minnesota. It’s a sprawling body of clear water, composed of numerous bays and points. Its shores, within the boundaries of Chippewa National Forest and the Leech Lake Indian Reservation, are wooded and just now greening up. ¶ As the boat lands on Little Pelican Island, two figures sneak ashore and duck into round plastic blinds. Thousands of black double-crested cormorants, common terns, and ring-billed gulls rise from the sand uneasily and settle again onto their nests. ¶ Then, as daylight turns the lake to a pool of mercury, the shots of .22-caliber rifles muffled by silencers come one after another. With nearly every one, a cormorant collapses in the sand. By midmorning, the men gather as many as 300 carcasses into plastic tubs and haul them back to the mainland. There they’ll be incinerated. ¶ Starting a couple of years ago, this scene has played out almost daily during the springtime. Sharpshooters from the U.S. Department of Agriculture’s Wildlife Services program killed about 3,000 cormorants last year alone to protect the lake’s renowned walleye fishery—one of the most extensive efforts to control cormorants in North America. Says Bill Paul, Wildlife Services assistant state director, “We’re in it for the long haul.”
Count Warren Anderson, the owner of Northland Lodge on Leech Lake, among the thankful. “I think they’ve handled it real well, though personally, I don’t think they’ve done enough.” In his opinion, the shooting should have begun sooner. “Basically the resort trade on Leech Lake is gone.”
Others oppose the killing. “I don’t think there’s any scientific justification for the Leech Lake effort,” says Linda Wires, a University of Minnesota research associate who has studied cormorants statewide and nationally. “There’s not been the hard science done to tie the walleye decline to the cormorant predation…. Some of us look at this as a true conservation success story.”
“Cormorants have become a scapegoat, I’m afraid,” says Mark Martell, director of bird conservation for Audubon Minnesota. “If loons were blamed,” he says, “I don’t think they would be taking this action.”
BUT THEY’RE NOT LOONS, they’re cormorants. While both are big deep-diving fish-eaters, the similarity ends there—at least in the opinion of walleye anglers, fishing guides, and resort owners.
Our beloved loon is known for a melodious tremolo, haunting wail, and distinctive yodel. It dresses in crisp black-and-white checks. In flight, it’s a jet; wind whistles from its wings. In early summer, mated pairs swim with a gray baby in tow—a nuclear family of state symbols.
The cormorant wears a long-tailed undertaker’s coat, and its voice ranges from a muddy bleat to a raspy shriek. Its beak hooks, and it struggles through the air with a flappy, broken-wristed wingbeat. Cormorants roost and nest on islands by the dozens, hundreds, or thousands, piercing the air with their cries, killing trees with accumulations of guano, and spreading their wings to dry (they lack the oiled feathers of other diving birds) as if they wore capes.
The trouble began a few years ago. After disappearing for decades, cormorants returned to Leech Lake in 1992, grew to 73 nesting pairs in 1998, and by 2004, numbered 2,524 pairs, all piled onto Little Pelican Island. Jim “Murph” Murphy, a longtime muskie and walleye guide, would watch as they flew across the lake in long, black lines. “They’d be coming and coming and coming,” he says. “It was just amazing.”
Where had they come from? Were they, as some residents believed, an invasive exotic species? Or a sign of an ecosystem gone awry?
For as long as naturalists have written about American birds, cormorants have been known to occupy the East and West coasts. “The double-crested cormorants are seen flying in long lines, sometimes forming angles, and passing low over the water, at no great distance from the shore,” wrote John James Audubon in Birds of America.
In the late 1800s, cormorants bred in most of Minnesota. Along the Iowa border, according to one observer, “the air [was] jist black with ’em an’ they’re nestin’ on the island so yer can’t see it for eggs.” Another reporter described a flock of migrating cormorants “four miles long and one-and-a-half miles wide.” A flock on the Mississippi was so dense “it was impossible to see the sunset sky through the mass.”
Fishermen disliked them then as they do now and killed “great numbers” on Lake of the Woods. But the most damaging blow was DDT. Passed up the aquatic food chain, the insecticide caused eggshells to thin, just as it did with bald eagles and peregrine falcons. And with the same results: broken eggs, few successful nests, and few birds. Cormorants disappeared from their familiar haunts.
But with the ban on DDT, protection under the Migratory Bird Treaty Act and the Clean Water Act, and a newfound winter food source—fingerling catfish from Deep South fish farms—cormorants are roaring back. They now number an estimated 2 million.
ON LEECH LAKE, fishing reigns. People still talk about the midsummer days in 1955 when giant muskies went on a rampage, striking lures like never before. Leech is still one of the best places in the world to catch a big one.
But while the lake is best known for muskies, it is the walleye—the feeble fighting but deliciously bland state fish—that is the bread and butter of the resort and guiding industry. The anglers who flock to northern lakes for the mid-May “fishing opener” are fishing for walleye—and launching the tourist business nearly a month before kids get out of school and families take their vacations. (Muskie fishing doesn’t heat up till midsummer.) Walleye fishing also pushes the tourist season deep into fall, long after schools reopen. The cormorant explosion threatens that, say locals in the fishing business.
An adult cormorant eats a pound of fish a day. At Leech Lake, that’s two to three tons of fish for each day of summer. That probably includes suitably sized walleyes, an icon perhaps even more beloved than the loon.
“It’s totally wrecked this lake for walleye and perch,” Murphy says. “The economy has been affected.”
“You could see it each year—the fishing started getting worse,” says Jeff Woodruff, who guides for both walleyes and muskies. Adds Steve Mortensen, biologist for the Leech Lake Band of Ojibwe, which owns Little Pelican Island: “There was no end in sight.”
Beginning in 1997, fisheries managers test-netted few small walleyes in the large bay where cormorants hung out. Young walleyes were more abundant in a deeper bay where cormorants were scarce. “I think there was enough evidence that something was going on,” Mortensen says. Resource managers were also concerned that cormorants were crowding out a dwindling population of common terns.
So the state Department of Natural Resources and the Leech Lake Band decided that federal Wildlife Services agents should begin shooting cormorants under a public-resource depredation order. The goal: to reduce the Leech Lake breeding population to 500 pairs. After nesting season, gunners would continue to kill 20 a week to learn what cormorants are eating.
But scientists wanted more time to study. “My main objection is that science has been put aside and public pressure is running the show,” says Francie Cuthbert, a University of Minnesota wildlife professor who studies colonial nesting birds. As for the threat to common terns, she says, “there’s no good indication that was occurring.”
“I don’t think we had the time to go through what Francie would have liked to have done,” says Harlan Fierstine, DNR fisheries supervisor in Walker. “Fishing isn’t everything here for the economy, but it’s very important.”
The DNR has been stocking walleye fry in Leech Lake—more than 22 million last year alone. That number, as large as it seems, is thought to make up less than 40 percent of the lake’s young walleyes. The lake produces the rest naturally. But stocking has always been part biology, part public relations. “We’re under political pressure to do so,” Fierstine acknowledges—“there is high public interest.”
Under federal permits, cormorants have been shot, their nests destroyed, and their eggs oiled in Wisconsin, Michigan, Ohio, New York, Vermont, Arkansas, Alabama, Mississippi, and Georgia. Private landowners have killed others on fish farms and commercial minnow ponds.
When will the shooting end? Not soon, to judge by the burgeoning Great Lakes cormorant population. Unless anglers give up walleyes, diners forgo catfish fillets, and people in general change their attitudes toward gangs of fish-eating birds, the killing will continue.
Greg Breining is a writer in St. Paul.