Friday, July 01, 2005

ENV: More cormorant problems

Protected Birds Return, With a Vengeance
By LISA W. FODERARO, July 1, 2005, The New York Times

FOUR BROTHERS ISLANDS, N.Y. - The double-crested cormorants perch like conquerors at the tops of the spindly white pines, their driftwood-gray branches devoid of needles. The trees were killed off, along with much of the other vegetation on the small rocky islands here in Lake Champlain, by the birds' highly acidic droppings.

As they have across the United States, double-crested cormorants, large migratory water birds, have proliferated on the lake in recent years: from none before 1980 to 3,800 breeding pairs last year.

The birds' ability to take over islands for use as nesting colonies where they can ruin the habitat for other birds and down tremendous amounts of fish has raised alarms among anglers, state environmental officials and wildlife biologists. But while officials in New York have worked to control the population elsewhere in the state - by oiling eggs, destroying nests and even shooting the birds - they have been stymied on Lake Champlain.

The cormorants here nest on the Four Brothers Islands, which are owned by the Nature Conservancy's Adirondack chapter. When the state's Department of Environmental Conservation asked the environmental organization for permission to "manage" the cormorants there, the conservancy politely but firmly declined.

The organization, which is amenable to controlling invasive or nuisance species, even by lethal means, says that the cormorant problem is too complex and broad to tackle in a vacuum. It plans to spend the next two years studying the issues before deciding what action, if any, to take on Four Brothers.

"There really isn't any comprehensive regional management plan to deal with the population," said Chris Maron, the chapter's Champlain Valley program director. "We didn't say 'no' forever. But we don't want to have the treatment take place on Four Brothers and just force the cormorants elsewhere."

The response by the conservancy was a blow to some recreational fishermen on the scenic lake, bounded on the east by the Green Mountains of Vermont and on the west by the Adirondacks of New York. They worry that the cormorants will eventually impinge on some of the popular catches. "They basically dive and feed and fly," said Jim Hotaling, of Willsboro, N.Y., a charter boat captain on the lake. "I think they most definitely hurt the fishery."

The state of Vermont, which has aggressively pursued the cormorants on Young Island, the site of the other major colony on Lake Champlain, was not happy either.

"We were a little discouraged," said John Gobeille, a district wildlife biologist with the Vermont Fish and Wildlife Department, referring to the Four Brothers decision.

For a second year, Vermont officials are shooting cormorants on Young, the six-acre island the state owns in Lake Champlain, once a lush preserve of basswood, elm, green ash and cottonwood trees that was host to black-crowned night herons, cattle egrets, great blue herons, fly catchers and orioles. Not only do the cormorants destroy trees and shrubs with their droppings, but they break off twigs and branches to build their bulky nests. "There are only gulls and cormorants now," Mr. Gobeille said of Young Island, adding that vegetation had been reduced to "garlic mustard, stinging nettle and thistle."

This summer Vermont plans to kill 440 cormorants, or 20 percent of the colony's population. Since the late 1990's, Vermont has also oiled thousands of eggs each year to prevent hatching. Those efforts have helped to cut the cormorant presence on Young Island from 3,000 nests in 1999 to 1,100 nests this year. During that time, however, the cormorant population on Four Brothers doubled.

"There is such a tight link among the cormorants on Lake Champlain, which is really just a small pond to them," Mr. Gobeille said. "It should be looked at as one colony, but because there are different states and jurisdictions and ownerships, it's been difficult to manage."

Historic records indicate that cormorants were present throughout the East when European settlers arrived, although none were documented on Lake Champlain. In the 1800's, cormorants were mercilessly hunted both for their feathers and because they competed for fish. The pesticide DDT depressed their numbers further in the 20th century. But since the 1970's, cormorants have rebounded under an amendment to the Migratory Bird Treaty Act. There are now an estimated two million in North America, according to the United States Fish and Wildlife Service.

Scientists and wildlife officials say the rise of sprawling fish farms in the Southeast, where cormorants spend the winter, has provided the birds with a tremendous new food source.

Scientists like David E. Capen, a research professor of wildlife biology at the University of Vermont and an expert on cormorants, say that this should mean more support to control the population.

"There's a human management of these populations in the wintertime by essentially giving them food, and to me, that's a very unnatural component," he said. "That's what justifies the management of the population on the breeding grounds."

New York State environmental officials have pledged not to touch Four Brothers without the conservancy's permission. "It is their land so we will continue to work with them on studying the cormorant population and their impacts," said Maureen Wren, a spokeswoman for the Department of Environmental Conservation.

Despite the protests of anglers on Lake Champlain, the cormorants have so far stayed away from the most prized species, eating mostly yellow perch and rainbow smelt. Indeed, there are so many yellow perch in the lake that their growth is stunted - a sign of overpopulation - and some biologists say their consumption by cormorants is a good thing. But elsewhere in New York, cormorants are going head to head with recreational fishermen for popular sport fish like smallmouth bass.

Against that backdrop, the Four Brothers Islands, which together measure only 18 acres, constitute a strange sanctuary - a smelly, noisy, barren landscape, seemingly plucked from a Hitchcock film. Lacking oil glands, the ubiquitous black birds can be seen stretching out their wings Dracula style to dry their feathers. The odor from their droppings is so strong that it is easily picked up from a boat some distance from the shore.

"Cormorants," said Adam E. Duerr, a graduate research assistant who works with Professor Capen, as he piloted a motor boat in the area, "have a long history of people not liking them."

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