Michigan's pesky water birds may be targeted again
Written by Detroit News   
Thursday, 24 May 2007 02:58

Nearly wiped out by pesticides in the 1960s and 1970s, double-crested cormorants are thriving. And some of the ravenous, hook-billed birds may have to pay with their lives for their species' comeback.

Cormorants are dark-feathered birds with wingspans that can reach 4 feet. They have a voracious appetite for alewives, trout, perch, salmon and other fish -- and are considered at least partly responsible for declining fish populations in several northern Michigan communities.

Critics say their presence has hurt tourism and fishing from the western Upper Peninsula to the northeastern Lower Peninsula.

On South Manitou Island in northern Lake Michigan, the National Park Service is deciding whether to kill 25 percent of the cormorant population this summer to protect giant cedars on the island's southwest shore.

The acidity of the bird droppings changes the pH level in the soil, causing trees and vegetation to die, said Steve Yancho, chief of natural resources at Sleeping Bear Dunes National Lakeshore.

"I guess our greatest fear is ... if we were to leave that area just to attend to itself, we could wind up with many more birds than we'd like to see," Yancho told the Traverse City Record-Eagle for a Sunday story.

The U.S. Department of Agriculture Wildlife Services killed one-quarter of the cormorants on South Manitou last year, said Peter Butchko, the agency's state director.

Officials either shoot adult birds or oil eggs in nests to prevent them from hatching. No nests were oiled last year, but 119 birds were shot, Yancho said.

Not everyone agrees that cormorants must be killed to be controlled.

In Alpena, the Michigan Nature Association is contesting authorities' efforts to control the cormorant population in Lake Huron's Thunder Bay.

Sherri Laier, stewardship director for the nature association, said there have not been sufficient studies to link cormorants to declining fish populations. Other changes in the Great Lakes, such as the emergence of the invasive zebra mussel, may be to blame because they deplete the lakes of nutrients at the bottom of the food chain.

Though cormorants are protected by an international migratory bird treaty, the U.S. Fish and Wildlife Service determined in 2003 that states could curb their numbers if they were harming natural resources.

"Naturally, the public is very concerned about what kind of impact the cormorants might have on the fisheries resource," said Dave Fielder of the Department of Natural Resources. "I've never seen in all my years an issue like cormorants and cormorant control."
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