[AU5B-C] November-December 2005 Audubon
Animal Control
Birds in the Bull's-eye

As day breaks over 112,000-acre Leech Lake in northern Minnesota, a boat lands on Little Pelican Island. Two figures sneak ashore and quickly duck into blinds. Thousands of double-crested cormorants, common terns, and ring-billed gulls, momentarily disturbed, settle again onto their nests. Then begin the muffled yet methodical shots from .22-caliber pellet guns. After two hours the government sharpshooters circulate among the nests and collect as many as 300 cormorant carcasses.

For a month this past spring this scenario played out almost daily as the United States Department of Agriculture's Wildlife Services unit killed 3,000 cormorants, about 80 percent of Leech's nesting pairs, to protect the lake's vaunted sport fishery. The cull, one of the most extensive control efforts in North America, will probably resume next spring.

“I think they've handled it real well, though personally, I don't think they've done enough,” says Warren Anderson, owner of Northland Lodge, about three miles from the cormorant colony.

While resort owners and anglers have demanded that the cormorants be controlled, the killing isn't universally supported. “A management decision is being made with no data to back it up,” says Mark Martell, director of bird conservation for Audubon Minnesota. “That's bad for birds; it's bad for fish.”

Leech Lake isn't unique. Under federal permits, cormorants have been shot, their nests destroyed, and their eggs oiled in Arkansas, Georgia, Michigan, New York, and Vermont. In 2004 more than 3,000 cormorants were killed on public lands and water, and thousands of eggs and nests were destroyed, says the U.S. Fish and Wildlife Service. Private landowners destroy far more—an estimated 30,000 each year—on fish farms and commercial minnow ponds.

Throughout much of North America, the double-crested cormorant has become a victim of its own success. Cormorant populations declined precipitously in the mid-20th century as the birds were shot and contaminated by pesticides. But as a result of the ban on DDT, protection under the Migratory Bird Treaty Act, and a new food source in the form of Deep South fish farms, cormorants proliferated, and they now number an estimated 2 million.

There have been repercussions. Adult cormorants eat about a pound of small fish daily. They congregate by the thousands, spreading their black wings to dry—a pose some people find frightening. “Cormorants have become a scapegoat, I'm afraid,” says Martell. “If loons were blamed, I don't think they would be taking this action.”

On Leech Lake, cormorants went missing for decades. They reappeared in 1992, grew to 73 nesting pairs in 1998, then to 2,524 in 2004. “There was no end in sight,” says Steve Mortensen, biologist for the Leech Lake Band of Ojibwe, which owns the island and is one of several agencies involved. Small walleyes disappeared as the cormorant population soared. “I think there was enough evidence that something was going on,” Mortensen says.

“I would question other mortality factors,” including weather and invasive species in the lake, says Linda Wires, a University of Minnesota research associate who has studied cormorants statewide and nationally. The control program “perpetuates this idea that we have to control nature,” she says. “Really we need to be controlling ourselves. There are a lot of other places people can go and fish.”
—By Greg Breining

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