The conservation team at Bernheim Forest and Arboretum is hoping to confirm a new addition to their growing family of eastern golden eagles that call the park home in the winter months.
As part of its ongoing conservation plan, the Bullitt County research forest captured a mature female eagle in 2019, now named Athena, and has tracked her annual migrations to northern Canada since then.
The team also captured Athena's mate, Harper, tracking the annual migrations of a mated pair of eastern golden eagles for the first time in recorded history.
"When Athena and Harper were paired together, they would take separate routes, but they would end up at the same area, the same nest in Canada within a couple of days of each other. And that's something that, as researchers, we still don't understand how they were able to find one another," said Bernheim natural areas manager, Evan Patrick.
Athena knows
Harper died in 2022, putting an end to their ongoing research into the mated pair's 1,700-mile migrations. However, Athena soon returned with a new mate. Patrick says despite the research team waiting in a wildlife blind for more than 40 hours, attempts to capture that new mate were unsuccessful.
"Athena was not going to let that happen. She knew exactly what we were doing, she knew the plan. For those days that we were sitting in the blind, there were many many hours that we could see Athena and her mate sitting about 300 yards from the blind, staring at our blind and knowing that we were in there," he recalled.
Despite unsuccessful attempts to capture Athena's mate, the team was able to capture a young male eagle, now named Hermes. He's now a key part of the conservation team's efforts to track independent young eagles.
Bernheim works in tandem with another eagle research team in northern Canada that has a trail camera observing Athena's eyrie, or nest, near Hudson Bay. That team reported that Athena and her new mate would likely have a juvenile in tow when they returned to Bernheim in the winter of 2023.
"Not only have they seen Athena's eyrie, but they have seen Athena on her eyrie with a young bird, so that was confirmed for us that she had a chick and has fledged that chick," Patrick said.
Andrew Berry, Bernheim's director of conservation, says that without that partnership, the team would know almost nothing about the birds' summer activity.
"We were able to coordinate with the Parks Canada researchers up there at Wapusk National Park, and they do reconnaissance into the park in the summer with helicopters, it's a really inaccessible and wild place in the summertime," Berry said.
After she returned to Bernheim, the team spotted Athena working cooperatively with a juvenile eagle that they believe to be her offspring. However, without capturing that juvenile, Berry says they can't be sure.
"You know, we're uncertain whether that means that she knows this bird and she's sharing a moment with it, or if this is just that she's an adult eagle and she's more tolerant of an immature eagle, something she wouldn't necessarily do with another adult, which would be more of a competitor," Berry said.
A chance for some unprecedented eagle research
Patrick hopes that in time, the team will have the opportunity to capture the juvenile while it is still bonded to Athena. That research would be the first of its kind for conservationists who study eastern golden eagles.
"There's very little known about how juveniles migrate once they've been fledged. We're not sure if they migrate with the adult or if they take their own migration route, but based on what we've seen from our trail cameras and from blind sits, it seems like at least for a couple of years the juvenile will migrate with adults. So, that's what we're seeing with our trail cameras and that cooperative behavior with the juvenile and Athena," Patrick said.
This isn't the first chick that Athena has successfully fledged, according to data from the Wapusk research team. With a lifespan of at least 30 years, Patrick hopes that this will not be the last juvenile that Athena guides on her annual migration.
"It's possible that Athena could have another ten good years, 15 good years still left, and Hermes might have another twenty. So, they're long-lived birds," Patrick said.
Protecting Bernheim's eagles
The team's conservation plan outlines the progress of the eagles migrations, as well as ongoing risks to the large raptors. Patrick says eastern golden eagles require massive swathes of intact, high quality habitats that connect multiple ecosystems. Those habitats are growing more difficult to find.
"If you're coming down the 65 corridor from Louisville, you can see just massive development. I've been with Bernheim for about five years, and the amount of habitat loss just in those five years that I've been here has been significant," Patrick said.
Other threats to the eagles include large windmills to collect electricity and lead ammunition used by hunters.
"A bird the size of a golden eagle can eat the amount of lead the size of a grain of rice, and that's enough to kill a bird of that size. So, say a hunter shoots a deer with lead ammunition, that lead is spread throughout the body of the deer, that deer is field dressed, the gut pile is left in the forest, a golden eagle happens to eat that gut pile and that can be enough lead to kill a bird," the naturalist said.
While there are risks to the eagles throughout their migratory path, Patrick and Berry say that Bernheim's 16,000 acres of diverse ecosystem remain the ideal winter home for the large birds.
Athena and Hermes have both returned to northern Canada for the spring and summer, and are expected to return to Bernheim at the end of fall.
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