Bald Eagle Shot Through the Heart – By a Loon!

By Wildlife Biologist Danielle D’Auria

Sometimes being a wildlife biologist means dealing with dead things.  We get calls about all sorts of dead critters people find in their yards, on the highway, or washed up on shore.  Sometimes we will collect these specimens for further study or to provide to a museum for preservation.  For instance, as part of a common loon mortality study, every year I encourage people to let me know if they find a dead loon so we can then have a necropsy (wildlife autopsy) done to determine the cause of death.  This allows us to understand the challenges these birds are up against, and how we can potentially alleviate those challenges. 

I deal primarily with waterbirds – loons, herons, black terns, marsh birds – so when I heard from John Cooley, loon biologist at the Loon Preservation Committee in New Hampshire, that there was a bald eagle found dead near a dead loon chick on Highland Lake in Bridgton last summer, I was intrigued.  The bald eagle was collected by Maine Game Warden Neal Wykes and brought to Norway Veterinary Hospital for a radiograph to determine if it had been shot.  No metal showed up on the image, but during the external exam a puncture wound on the eagle’s chest was discovered.  This puncture wound could have been due to an adult loon’s beak as a result of its attempt to protect its chick from the eagle.  A loon’s best weapon is its dagger-like bill, and it will often attack adversary loons by coming up from beneath the water’s surface with its bill straight towards the other loon’s sternum, or chest.  Many adult loons have several healed-over sternal punctures from fights like these.

Bald eagles are protected by the Bald and Golden Eagle Protection Act, and typically all dead eagles are sent directly to the National Eagle Repository in Colorado, so their parts can be properly distributed to Native Americans for ceremonial purposes.  We obtained special permission from the U.S. Fish and Wildlife Service to send this individual to the National Wildlife Health Center in Madison, Wisconsin, for a thorough necropsy to determine if it indeed could have been killed by a loon.  The reason this is so interesting to loon researchers is that such a case has not been documented before.  We know conflicts between bald eagles and loons have soared in recent years as a result of the recovery of our eagle population.  We are seeing more and more eagle predation on loon chicks and even adult loons.  Who would think a loon would stand a chance against such a powerful predator?

Sure enough, the pathologist who examined the eagle and loon chick in the lab, called me shortly afterward to tell me it indeed looked as though the loon was the culprit in this eagle’s death.  The size of the puncture wound was similar to the size of a loon’s bill, and it extended straight to the heart which likely led to a quick death.  Not only that, but the loon chick had puncture marks consistent with the spacing of eagle talons.  There were no witnesses of what transpired.  Nat Woodruff found the dead eagle floating face-down at 6am, and appropriately left it there while he contacted the Warden Service. Warden Wykes first came upon the dead loon chick and then the eagle.  The only other information we know is that a woman in a nearby cabin had heard a “hullabaloo” the previous night, consistent with agitated loons.  You can use your imagination to formulate how this all played out on Highland Lake that late July evening.