When a bald eagle showed up dead in a Maine lake last summer, authorities suspected it might have been shot. But when an X-ray failed to find signs of metal in the bird’s chest, the veterinarian found something else—a stab wound straight into the eagle’s heart. The case became a wild whodunnit.
To solve the murder mystery, the eagle’s remains were sent to the National Wildlife Health Center in Madison, Wisconsin, for a thorough necropsy, wildlife biologist Danielle D’Auria explains in a blog post for the Maine Department of Island Fisheries and Wildlife. There, the identity of a likely culprit emerged. The puncture wound matched the size and shape of a loon’s straight, dagger-like bill.
But what about motivation? Near the dead eagle, Maine wildlife warden Neal Wykes had found a dead loon chick. In Wisconsin, the pathologists confirmed that its wounds matched the spacing of an eagle’s talons. All together the evidence suggests that when an eagle swooped in to steal a loon chick for a snack, the loon parent took revenge.
"From our understanding, this is the first time this has been documented where it [a loon] has actually killed an eagle, a pretty top predator,” D'Auria tells Dustin Wlodkowski at NECN. “That's why it was pretty fascinating."
Loons are a well-loved diving bird that can be found on wooded lakes throughout the northern United States and Canada, known for their low-pitched songs that can be heard across a body of water. They appear tranquil and proud—and sometimes adorable, carrying fluffy chicks on their backs—they’re also savage fighters. They’re known to fight ducks and Canada geese, and normally aim their stabbing bills at each other. As D’Auria writes, adult loons often have multiple healed puncture wounds on their chests.
“It’s been going on for millennia,” says The Loon Preservation Committee senior biologist John Cooley to Jason Bittel at National Geographic. “It’s survival of the fittest happening on our lakes.”
Altercations between loons and bald eagles are a relatively new phenomenon to wildlife biologists because for decades, bald eagle populations were so low. But as their population recovers, the interactions are happening more often as the eagles prey on loon chicks and sometimes even adults. That an adult loon could fend one off caught biologists’ attention.
"Word got around that this eagle had been found dead," D’Auria tells NECN. "I heard about it through loon researchers who had heard about it through a wildlife rehabilitator."
Normally when an eagle is found dead, its remains are sent to the National Eagle Repository in Colorado, so that its parts can be distributed to Native Americans for ceremonial purposes, D’Auria explains in the blog. Researchers had to obtain special permission from the U.S. Fish and Wildlife service to get a fuller understanding of the circumstances of its death. And while the event may seem like a tragedy for the eagle and the loon chick, Cooley explains that the event is a good sign for conservation efforts.
“We want natural problems like this to replace the human-caused problems, like lead fishing tackle as a source of mortality,” Cooley tells National Geographic. “You know, we’re living for the day when eagles are the worst thing that loons have to deal with.”
It seems that when eagle populations plummeted as a result of DDT, habitat destruction and illegal hunting, loons came to rule the roost. But now that eagles are recovering, the two species must duke it out and find a new equilibrium.
“There’s a balance,” Vermont Center for Ecostudies loon biologist Eric Hanson tells National Geographic by email. “Eagles need to eat, and loons will defend their chicks as best they can.”
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