Cormorant cull on Lake Erie ongoing

Posted on June 17, 2010

Oak Harbor, Ohio - DNR authorities continue to cull cormorants from a trio of Lake Erie islands.

The DNR_Division of Wildlife manages the birds on Lake Erie through a Public Resource Depredation Order issued by the U.S. Fish and Wildlife Service. Since cormorants are migratory birds and thus protected under the Migratory Bird Protection Act, any lethal management of the species must be approved by the federal government.

This was the fifth year for cormorant control efforts on Lake Erie's West Sister, Green and Turning Point islands, said Dave Sherman, a waterfowl biologist for the Division of Wildlife.

Control efforts this year, which included the removal of nearly 2,200 of the fish-eating birds, took place in late April and early May before spring foliage took hold, Sherman said.

"Each year, (the cull) has gone down a little bit," Sherman said. "We haven't hit 3,000 in quite a while."

Last year, 2,300 cormorants were killed with noise suppressed rifles, said Sherman. In 2008, the number was 2,600.

All of which points to the success of the management effort, which began in 2006.

"The islands seem a lot greener," Sherman said, "especially at Green and West Sister. At Turning Point, the numbers are a little bit higher than we'd like to see them still. We haven't seen the results there that we'd like to see."

Turning Point Island is a small patch of land that lies just outside the city of Sandusky.

Sherman said the initial plan was to see some results in the program within five years. This was the fifth year.

"We're still taking vegetation surveys," he said. "That should allow us plenty of lag time to see scientifically whether the trees are greener. From an anecdotal standpoint, just looking at (the islands), it's a lot greener. You just don't see any dead trees there."

Cormorants expel an acidic guano that kills the leaves on the trees, eventually killing the trees themselves, Sherman said. That isn't happening with the same frequency as it did before cormorant control efforts began, he said.

"On West Sister, we have a zone in the northeast corner where we don't do any cormorant removal," he said. "So, that area has a lot of cormorants nesting in it, so we'll see what kind of effect that has. I expect the vegetation will deteriorate in that area."

Canadian authorities also conducted some cormorant control efforts on its portion of Lake Erie.

"That will help reduce the overall numbers in the Lake Erie basin," Sherman said.

Also working under the USFWS_rule, the state of Michigan has by far culled the most cormorants, Sherman said. This year, DNR_authorities in that state killed more than 10,000 birds.

Ohio has to apply each year for the federal order and then submit a management plan to take more than 10 percent of the population. The plan is to continue control efforts in 2011, but progress is being made, Sherman said.

"Now, we're just going to West Sister once where before we were going there two times," he said. "So, hopefully we'll be able to reduce effort on Green and Turning Point, as well."