Efforts to reduce cormorant populations paying off

BURLINGTON, Vt. (WCAX) A shorebird with an intense appetite and destructive droppings is on the decline in Lake Champlain. A multi-year effort by Vermont Fish and Wildlife, the New York DEC, and private land owners to reduce the cormorant population appears to be paying off.

Researchers says in 2008 there were almost 4,500 cormorants on Lake Champlain. In 2018 that number has dropped to just under 2,400.

Retired University of Vermont Professor David Capen has been researching cormorants on Lake Champlain for more than a decade. On Young and Bixby Islands -- west of Grand Isle on Lake Champlain -- is where the decline in the populations is visible.

"Cormorants are pretty wary of islands that have people on them," Capen said.

Cormorants have recently started nesting on the privately-owned island anyway, but it's certainly not as devastated as it's neighboring island -- Young Island -- owned by the state of Vermont.

For decades Vermont Fish & Wildlife officials have been oiling eggs to prevent them from hatching and having the birds destroy vegetation and eat large amounts of the lake's fish. But Capen says seeing results takes time. "No one gets instant satisfaction," he said.

Vermont Fish and Wildlife biologist John Gobielle says the department started culling the birds as a quicker option back in 2004. "That's very quickly removing the cormorant issues," he said.

But private land owners and Vermont Fish and Wildlife needed to get federal permits to do this because cormorants are a protected migratory bird. And Capen says the birds just move to a different island.

He says in 2004 there were more than 1,400 cormorants on Young Island and more than 2,300 on the Four Brothers Islands in New York's part of the lake. This year there were no cormorants nesting on Young Island and More than 2,200 on the Four Brothers Islands. That's almost the lake's entire cormorant population.

"There are two islands in the Four Brothers that have lost most of their trees," Capen said. Meanwhile, trees and grasses have started re-growing on Young Island.

Gobielle says bald eagles may be a natural and more effective solution. They're making a comeback on Lake Champlain and prey on cormorants. Bald Eagles in the Missisquoi National Wildlife Refuge and at the Sand Bar State Park have helped cut down on cormorants in those areas. "We've been using big eagle decoys on our islands, because we realized you do get some effective control," Gobielle said.

A 2016 lawsuit against the U.S. Fish and Wildlife Service limited the number of cormorants that can be culled. Vermont Fish and Wildlife officials say they are still trying to determine how that will affect the state's cormorant population management.