In early October, we were collecting seed in Sand Prairie when I heard a persistent, urgent eagle call coming from the direction of the marsh. I searched the sky and saw a determined-looking adult Bald Eagle hurrying into the sky over my head. After a bit of searching, I spotted, high above, seven more adult eagles kettling slowly and heading south. One of them dropped down to respond to the “local.” A brief confrontation ensued, with some calling, rolling, and talon threats, but no contact. The incident ended with the “intruder” floating off to the south with its companions, and “our” eagle flying back toward the marsh, presumably to continue fishing.
According to the Cornell Lab of Ornithology’s Birds of the World, this encounter falls in the category of “agonistic” behavior. Eagles do engage frequently in agonistic behavior, particularly when competing for resources in winter. During the nonbreeding season, Bald Eagles often congregate in large groups around fish kills or carrion, where they fight over the food. They also come into conflict over favorite perches or roosting sites.
Adult eagles may have territorial disputes during the breeding season as well. We have seen many confrontations when outsiders come too close to our resident nest. We first recorded Bald Eagles nesting at Fair Meadows in 2010, and it has been monitored as part of Southern Wisconsin Bird Alliance’s Bald Eagle Nest Watch program since 2019.
Bald Eagles nest in a cottonwood tree in 2014. The fluffy nestling’s head is just visible above the edge of the nest (photo by Gary Shackelford).
Juveniles in the “cradle” nest in 2017 (photo by Gary Shackelford).
We discovered the first nest in a large cottonwood at the southern edge of the large marsh on the western part of the property. The eagles nested there through 2016, fledging one to three eaglets each year. In 2017, we discovered a new eagle nest on the eastern part of the property about a mile away. Because this was the very same year that the first nest was abandoned, we believe the same nesting pair had just decided to move. The new nest was in a large white pine. The tree had been hit by a tornado in 2005 and had grown a circle of new branches around the top creating a “cradle.” That nest was also very successful each year until 2021. That year, the adults began incubating, but abandoned the nest in March after an extremely long cold spell. We wondered if Lake Koshkonong had completely frozen over, thus creating a scarcity of food so the eagles had to move downriver to find fish. In 2022, they were back and fledged one eaglet. In 2023, they built another new nest and moved again, this time to a nearby white pine with a damaged top about 40 yards away. In both 2023 and 2024, three eaglets fledged.
We hope to see the eagles nest here again this winter!
Written by Penny Shackelford, Fair Meadows Sanctuary resident manager
Cover image by Gary Shackelford. An adult Bald Eagle is perched in the white pine “cradle” nest in 2017.
