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Eagle vs. cormorant: What to do when one rare species starts eating another?

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Bald eagle vs. great cormorant. It sounds like the title of a bad SciFi Channel movie, but it's actually a serious situation that has Maine conservation officials in a quandary.

Bald eagles (Haliaeetus leucocephalus) left the U.S. Endangered Species List in June 2007, after a remarkable recovery, but they are still legally protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act, which prohibit killing eagles for any reason. There are now more than 10,000 breeding bald eagle pairs in continental United States, up from less than 1,000 birds in the 1950s.


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Great cormorants (Phalacrocorax carbo), while not endangered, are quite rare in Maine, with just 80 breeding pairs left, down from 250 pairs 15 years ago. One of the reasons the birds have declined in the state is that they are being predated upon by bald eagles, which appear to be turning to seabirds for their food supply as fish populations in the area have shrunk.

"These young eagles are harassing the bejesus out of all the birds, and the great cormorants have been taking it on the chin," Brad Allen, wildlife biologist with the Maine Department of Inland Fisheries and Wildlife, told USA Today.

And it's not just happening in Maine. USA Today cites examples of bald eagles eating other birds in Alaska, Illinois and other states.

Right now, there's not much that can be done to protect the great cormorant. It's not legally protected, so no one has a requirement to do anything. Meanwhile, no one can legally do anything to dispel the eagles and prevent them from eating rare birds. If only there were more fish for them to eat.

But that's a whole other can of worms.

Image: Bald eagle, via Wikipedia