Raptor may set record

Cory Hatch
December 22, 2006

A female golden eagle captured as part of a research project in Buffalo Valley might weigh more than any other scientists have found in the United States.

The bird, captured Nov. 13 by Beringia South researchers, weighed 18.5 pounds. Female golden eagles in America typically weigh 8 to 13 pounds.

Bryan Bedrosian, one of the researchers who captured the bird, said the animal’s crop, a muscular pouch in a bird’s throat used to temporarily store food, was “about the size of a softball” and full of meat at the time of capture, which may have contributed an extra 1.5 pounds.

But even without the full crop, the animal still has a shot at the record books.

“We didn’t realize it at the time, but once I looked into the records I realized how big it was,” Bedrosian said. “That [crop] brings the total weight down to about 17, but that’s still about 3 pounds heavier than the heaviest birds that have been recorded in the U.S.”

Bedrosian said the animal was captured with a device called a whoosh net as it feasted on a road-kill elk that the researchers had set out for bait. While other eagles were spotted in the area, the large bird had the elk carcass to herself.

“Typically, when a golden eagle goes on a carcass, it dominates,” Bedrosian said.

The large female, estimated to be more than 5 years old, was the first golden eagle the team had captured in a couple of years, though it has captured more since.

Beringia South, a research group based in Kelly, is collecting blood samples from eagles and ravens to find out if the birds have lead poisoning. The scientists think birds that feed on gut piles may ingest bullet fragments, causing elevated lead in the blood.

But Bedrosian said the large female eagle had no apparent lead contamination.

“The bird looked really good ... really powerful and big,” he said, explaining that the bird didn’t struggle any more than other birds researchers have captured. “You definitely felt it a lot more when she moved. She was that much more powerful.”

The strange thing, Bedrosian said, is that the measurements of the bird, other than the weight, were fairly typical for a large female golden. An average-sized female is 32 inches long with a wingspan of 78 inches. Female golden eagles, like most raptors, weigh more than males.

For Bedrosian, the next step is to confirm the record and then, if no bigger birds are found, publish the results in a scientific journal. Researchers took a blood sample from the bird, attached an aluminum leg band and released her back to the wild.

Buffalo Valley is east of Moran Junction.