PLATTSBURGH — Scientists studying cormorant populations on Lake Champlain have seen a drop in numbers that is approaching an acceptable management level.
For years, anglers and other lake enthusiasts have voiced concerns about a growing number of cormorants on the lake, citing the waterfowl’s negative impacts on fish populations and on the vegetation where the birds breed and raise their young.
The Lake Champlain Basin Program recently released a study that observed management practices for cormorants living on Four Brothers Islands near Willsboro.
“It’s a continuation of work we started on cormorants back in the 1990s,” said David Capan, a retired professor from the University of Vermont who has continued his research beyond retirement.
“Four or five years ago, we were able to develop some coordination amongst agencies across Lake Champlain on how to develop management practices.”
REFUSED TO MOVE
A lot of the focus on cormorant populations was directed toward Four Brothers Islands because that area holds the largest breeding population on the lake by far.
With approval from the islands’ owner, the Adirondack Chapter of Nature Conservancy, Capan spearheaded a plan to oil the eggs of cormorants nesting on the islands. The process prevents the eggs from hatching but influences the adults to continue caring for them without trying to breed again.
“We tried targeting the two islands that were most valuable to other nesting birds,” Capan said, nothing that they have a healthy vegetation cover while the other two are void of growth.
“That didn’t work out as well as we hoped,” he added. “We were oiling heavily on islands A and B, hoping to push the nesting adults to the (two denuded) islands, but after four years of reducing the number of young on those islands, the adults were not moving.”
The egg-oiling project reduced the number of young on islands A and B by 85 to 90 percent, he noted.