So what happened in Decorah this year? The quick version: UME-2, who we will be calling DM2 from now on, is Mom’s current and third suitor since Dad disappeared in April of 2018. To the best of our knowledge, this is what happened…
As watchers know, Mom lost her mate Dad following a heavy snowstorm in April of 2018. A male eagle that we called UME and then DM turned up shortly after Dad’s disappearance, and we believed that he would eventually become Mom’s new mate. However, uncertainty about the male eagle that turned up in the Decorah nest in mid-October led us to question that narrative. John, our moderators, and our camera operators spent a lot of time combing through videos and images, discussing their thoughts on the matter, and capturing close-ups of the eagles. We eventually concluded that Mom had three suitors instead of the one we had assumed. We called them UME/DM, DM-1, and UME-2/DM2.
Dad disappears. Male eagle number one shows up
Timeline: April 19, 2018 to early July 2018.
What happened: Dad Decorah disappeared and a new male eagle showed up shortly thereafter. We started calling him UME (Unknown Male Eagle) but changed it to DM, for Decorah Male, a week or two later.
UME/DM Slideshow. Roll over the image and click the arrows to move right and left
What we saw:
- Mom did not allow DM on the nest, but he was frequently seen sitting in the maple with Mom and in the tree above the bridge and bike path.
- Mom sometimes behaved aggressively toward DM
- DM did not behave aggressively towards the eaglets
- DM did not participate in caring for the eaglets
DM disappears. Male eagle number two shows up
Timeline: Early July 2018 to mid-September 2018.
What happened: While we didn’t realize it until later, DM was replaced by another male eagle. We don’t know what happened to DM. We called this eagle DM-1 once we identified it.
Eagle #2 Slideshow. Roll over the image and click the arrows to move right and left
Why didn’t we realize the change right away?
- We didn’t see or hear a fight
- Mom and DM-1 were molting and showing signs of blackfly stress, which changed their appearance. John had to look at very small differences in iris patterns and beak morphology to determine that we had a new male eagle on Mom’s territory
- We weren’t seeing much of the eagles, which didn’t give us much data to go on
- Mom interacted with her first and second suitors in much the same way, although DM-1 was sometimes seen perched by the post-fledgling eaglets near N1. He was never seen on N2B that we are aware.
DM-1 disappears. Male eagle number three shows up
Timeline: Mid-September 2018 to current day.
What happened: DM-1 was replaced by a third male, who we ended up calling DM2. We don’t know what happened to DM-1.
DM2 Slideshow. Roll over the image and click the arrows to move right and left
What we have been seeing:
- DM-2 perches with Mom in the maple, on the bluff, and on the Y-Branch
- DM-2 flew into N2B on October 15, 2018. Mom joined him on October 24, 2018 and the two began nestorations
- DM-2 has had significant interaction with Mom, including nest building, attempted copulation, mutual territorial defense, and ‘Mom on top’ (dominance display). She did not engage in nest building or copulation with the other two eagles that we saw. She defended her eaglets, but we’re not sure that she joined the adult males in territorial defense.
Subsequent productive males in Decorah will get the moniker DM (for Decorah Male) followed by a long count number. Why not Dad2? There can be only one Dad for us, and he’s gone now.
We learned a lot following Dad’s disappearance, but we’re still curious about a couple of things. While the Decorah Eagles nest hasn’t been completely free of disruption, we saw what looked like an increased number of territorial fights following Dad’s disappearance, including talon-locking, ground-spiraling fights on April 20th and the week of October 26. Absent a catastrophic event or human persecution, eagles are their own worst enemies and populations tend to be self-limiting. Is what looked like an increase in territorial fighting just the result of more eagles in the area, or were male eagles competing for a lone female with a highly desirable territory and pre-built nest? Now that Mom has selected a mate, we’ll have to see if the number of adult male intruders falls off, remains level, or increases.
While male eagles tend to fight males and female eagles tend to fight females, we often saw Mom and Dad work together to chase off intruders. Did Mom ever join DM or DM-1 in territorial defense? If Mom didn’t join them in territorial defense, did her lack of action help keep the territory in flux? Again, the number of adult male intruders moving forward might provide some answers to our questions.
We wish Mom and DM2 the best of luck at N2B in 2019 this year. While we are trying not to count our eggs before they are laid (let alone hatched!) we can hardly wait to see the next chapter of the Decorah Eagles story! Thank you so much for watching, following, and learning along with us.
A Guide to the Terms
- Dad: Mom’s first mate. She was about 4.5-years old when she first showed up on the territory, so he was very literally her first mate. They were together from the fall of 2007 until Dad disappeared in April of 2018.
- UME. He showed up on Mom’s territory shortly after Dad disappeared. Since we didn’t know anything about him, we gave him the moniker Unknown Male Eagle.
- DM: Decorah Male. How long could this new eagle remain unknown? After a couple of weeks, we decided to give him a name that reflected what we thought was his status as Mom’s new mate. Since Dad was out of the question, we called him Decorah Male.
- DM-1: Decorah Male 1. He replaced UME/DM in early July of 2018. But why didn’t we call him DM2, or why isn’t DM DM-0? This was new and unexpected territory for us and we did the best we could with what we knew at the time. It was a shock to us to learn that there had been two eagles instead of one, and we didn’t realize it until long after DM-1 replaced DM.
- UME-2: Unknown Male Eagle 2. He replaced DM-1 in mid-September. But wouldn’t he be UME-3? We called him UME-2 before we knew this was the third eagle on territory and didn’t want to change it since things were confusing enough!
- DM2: After picking ourselves up off the Confusion Couch, we decided that potential mates had to earn Mom’s approval before we hung ‘Decorah Male’ on them. Simply being there isn’t enough – we need to see nestorations, attempted or actual copulation, and plenty of interaction! We also did away with the hyphen.
- N2B: Nest Two Bob. This originally human-built nest was named for our founder Bob Anderson, who approved it but died before we could complete it. We probably should have named it N3, but we wanted to memorialize Bob and this is one way we did so.
The Raptor Resource Project