Flourishing eagles feast on Maine's rare seabirds

ByABC News
May 19, 2009, 3:21 AM

PORTLAND, Maine -- Bald eagles, bouncing back after years of decline, are swaggering forth with an appetite for great cormorant chicks that threatens to wipe out that bird population in the United States.

The eagles, perhaps finding less fish to eat, are flying to Maine's remote rocky islands where they've been raiding the only known nesting colonies of great cormorants in the U.S. Snatching waddling chicks from the ground and driving adults from their nests, the eagles are causing the numbers of the glossy black birds to decline from more than 250 pairs to 80 pairs since 1992.

"They're like thugs. They're like gang members. They go to these offshore islands where all these seabirds are and the birds are easy picking," said Brad Allen, a wildlife biologist with the Maine Department of Inland Fisheries and Wildlife. "These young eagles are harassing the bejesus out of all the birds, and the great cormorants have been taking it on the chin."

The recovery of the bald eagle population has been well-documented, growing from 400 pairs to more than 10,000 pairs in the lower 48 states since the 1960s. But the revival has changed the natural order of things in Maine and other states, threatening other bird species.

With more eagles around and fewer fish in the waters than in the past, young eagles are turning to other birds to satisfy their hunger. Eagles are opportunistic feeders and will go after the easiest prey they can find, bird experts say.

In Alaska, many eagles have shifted their diet from fish to seabirds. In the Midwest, they've been known to eat baby blue herons. And besides Maine's great cormorants, eagles are also feasting on baby double-breasted cormorants, gulls, eider ducks and even loons.

Nobody's raising a stink about the eagles' taste for double-breasted cormorants and gulls because those birds are so numerous and considered nuisances by many.

But the great cormorants are another matter, because their numbers in Maine are so small, said John Drury, of Vinalhaven, who's been counting seabirds on Maine islands for more than 25 years. Although the birds are widespread from Europe to eastern Canada, they are uncommon in Maine, which represents their southern range in the Northwest Atlantic.