If you’ve been watching the Decorah Eaglecam, you know that a new eagle pair appears to be settling into the starter nest we built at N1. I’ll be honest: a lot of us have mixed feelings about that! We hoped the nest would lure Mom and DM2 back to the hatchery, but they chose to nest in N3 again this spring. Still, their behavior this fall gave us a little bit hope that they might make a different decision in 2023. That won’t happen if this new pair makes N1 or N2B their home.
April 11, 2022: The new eagles. He’s left, she’s right, and they look a lot like Mom and DM2. We can see some subtle differences up close and we’re working on iris fleck and feather catalogs.
Could they lay eggs yet this spring? They are clearly a bonded couple and we’ve seen them copulating, but they don’t currently appear to be getting a nursery ready at N1 or anywhere else that we know about. We don’t think it can be ruled out, but we don’t think it is especially likely given the current level of nesting activity. We’ll see if that changes.
April 10, 2022: I miss seeing Mom up close, but this new new female eagle is lovely! We’ll worry about official nomenclature if they stay, but I’m enjoying everyone’s pet names for now.
A lot of you are wondering where these eagles came from. While they could have come from an established territory with a failed or collapsed nest, they might also be a new pair that established a bond on their wintering grounds! Bald eagle winter pair formation has been documented by a few researchers, although we don’t think it is especially common*. There are a handful of places in the Decorah area where bald eagles congregate and large congregations on the Mississippi River are just 30 or 40 miles away: no distance at all to a pair of newly bonded bald eagles looking for a peaceful place to nest. We’re really excited to be watching what might be an uncommon behavior play out right in front of us!
What will Mom and DM2 think about a new pair? The Decorah territory is rich in food and eagles have been documented nesting relatively close together in landscapes that will support it. Perhaps this is one of the ways that nesting pairs increase on a landscape that will support it. These eagles also might not be bonded to the territory given that they haven’t been here long and haven’t started working on N1, N2B, or a new nest. We’ll see what they do this fall!
April 11, 2022: “Maybe I’ll wait to take a break…”. Mother Goose was just covering her eggs when the eagles started to vocalize. She settled back over them until things calmed down.
What do the geese think about all this? For the most part, the eagles and geese seem to be ignoring one another. But we’ve seen and heard a few interactions, and Mother Goose tends to wait for breaks if the eagles are nearby or active. We haven’t seen any eagles land in N2B or harass Mother Goose directly.
Eagle followers have been asking if one or both of these eagles could be Mom and Dad’s offspring. We don’t have any way of knowing for sure, but eagles, especially male eagles, are highly philopatric – that is, they tend to nest in the region of their birth. So it is absolutely possible that one or both of them could be from the Decorah nest.
* I was able to find references to winter pair bond formation in Harmata, A. R. (1984). Bald Eagles of the San Luis valley, Colorado: their winter ecology and spring migration, a bulletin from the Nebraska Game and Parks Commission, and Dynamics of a year-round communal roost of Bald Eagles in the Wilson Bulletin, 104(3), 1992, pp. 536-540. In the Wilson Bulletin, the author writes: Palmer (1988) suggested that pair formation among Bald Eagles can occur before definitive feathering and may come about through the extended association of pre-breeding individuals. At least one potential breeding pair (an adult male and Basic IV female) was formed at the ENP roost during this study. The high degree of interaction I observed between subadults, e.g., pursuit flights and talon grasping, as well as the increased level of aggression by eagles during the nesting season may facilitate mate selection. We’ll be reading a lot more about this – it certainly casts an interesting light on some of the behaviors we see on our Flyway cam!
The Raptor Resource Project