By Andrew Berry
Just in time for Valentine’s Day Week, love soars again at Bernheim Arboretum and Research Forest, where the esteemed female golden eagle Athena has found a new partner.
This comes several years after the loss of her longtime mate, Harper, who together became the first tracked pair of golden eagles in eastern North America. Not much is known about how golden eagles find or choose a mate, and even less is known about how they replace a lost mate. Working with our golden eagle research partners in the remote interior of Bernheim, we continue to unravel some of the mysteries kept by these long-distance migrants that reside in large forests of Kentucky during the winter months.
Audio (listen below) captured during January demonstrates calling between Athena and the other male golden eagle. We believe the male to be the high-pitched call, and the female to be the lower call. Together they sound the alarm, possibly a dual purpose to communicate with one another and to let the intruder know to beware. These calls were made as a bald eagle approached the pair while perched high in a white oak on the ridgeline. We observed the pair sitting together for long periods over several days, chatting and calling back and forth, and taking turns flying off perch, once hitting an approaching bald eagle in an aggressive aerial attack.
Athena was first identified as the mate of the male golden eagle Harper before being first tracked in 2019. Harper, first tracked in 2015, was observed spending time with another eagle, and his tracks showed he was spending the summer at a nesting site in Wapusk National Park in Canada. This tracking data was a clue that they could be a pair of cooperating golden eagles, because their activity occurred during nesting season, when females who remain on the nest laying eggs, fledging chicks, and defending the nest are dependent upon males for hunting and supplying food.
Unfortunately, Harper was lost in the wilds of Canada in April 2021, and indications from tracking showed he died while on a hunting trip while Athena was at the nest. Within days of his departure, Athena was forced to leave the nest site and begin hunting and roaming their territory for the remainder of the summer. Her tracks that summer suggested that she was alone, and her migration the following fall took her far from her usual route. Instead of flying through Michigan, she followed a route used by her mate through Wisconsin. She spent additional time in Wisconsin on this migration, and while she was at Bernheim last winter, she traveled more widely, possibly in search of a mate.
It seems her excursionist behavior paid off, and by late last winter she was spotted with another eagle at Bernheim. They seemed to tolerate each other’s presence. Over the next few weeks, she continued to be seen in proximity to this eagle. We were also very happy to document that Athena’s tracks in Wapusk National Park in the summer of 2022 suggest that she was on the nest for long periods. This timing corresponds to laying and hatching an egg. In fact, she continued to display behavior that suggests she may have fledged a chick. This would be impossible without the cooperation of a male golden eagle.
Could this be the same bird we now see Athena cooperating with at Bernheim? Could their offspring be the same juvenile we are now seeing in the vicinity of both Athena and the new bird? Is the new pair migrating together to Wapusk, and if not, how would the new couple find each other? And where do golden eagles meet potential mates, on the winter or summer grounds? We are not able to answer these questions yet, but we continue to ask questions such as these to advance our knowledge of these magnificent apex predators.
Stay tuned for more information as we approach the spring migration in early March. A special thanks to Beckham Bird Club, Cellular Tracking Technologies, Conservation Science Global Inc., and all the supporters of Birds of Bernheim that make this incredible project possible. The support from Bernheim’s members, volunteers, staff, and donors are what allow us to protect golden eagles and steward their large forest winter habitats.