Your dispersal questions, answered!

Where are D34 and DN12? Can the eaglets hunt on their own yet? When will they disperse? Your questions, answered…as best we can!

Where are D34 and DN12?
The short answer: we don’t know. Neither eaglet has been seen for several days and we didn’t see or hear D34 when we were in Decorah last week. Most of the eaglets that we have studied slowly widened their explorations prior to dispersal. But some (D25 and D1, for example) began adventuring with very little warning. Given what we have seen and heard on our cameras, we think D34 and DN12 may have left. Will we see them again? We could! On July 31, 2016, D25 left Decorah, flying north to Wabasha, MN (home of the National Eagle Center!) before returning to Decorah (and a few more glimpses on camera) on August 6. But they could be gone for good, too. On August 14, 2011, D1 left home with no warning and very little pre-dispersal wandering. Her last night in the nest can be seen here: https://youtu.be/hEo5hZl73Z0.

Are D35 and D36 catching their own food yet?
None of us have seen them fishing the retention pond or raceways yet, but Amy saw D36 wade into Trout Creek and foot a live fish out of the water, so the answer is yes! That we know, the two eaglets aren’t yet fishing from the air, but they are very proficient at finding food, whether it be a shallow-water trout, a dead opossum, a parent’s catch, or a sibling’s meal. Both eaglets are spending a lot of time following and learning from Mom and DM2, so it’s a just a matter of time before we see one of them make a classic catch from the pond. In the meantime, they are finding (and stealing) plenty of food!

When will D35 and D36 disperse?
Brett Mandernack found that eaglet age at dispersal from the Decorah nest averaged 162 days, or nearly 85 days after fledging. D35 and D36 are turning 126 and 123 days old today, so we still have a little over a month if both conform to the average dispersal date – a little more likely with D36 than D35 based on our findings so far. I am watching their behavior and maps for clues that they are ready to disperse – longer exploratory flights, the ability to catch food on the fly, and longer periods away from the N2B and N1 trees are all good indicators that they are ready to disperse. You can learn more about Brett’s findings here: https://www.raptorresource.org/2019/04/08/satellite-tracking-decorah-iowa-fledgling-bald-eagles-2011-2018/.

Do male or female eagles disperse first?
So far, male eaglets have dispersed slightly earlier than female eaglets (161 days on average versus 163 days on average). However, female eaglets have been much more variable in their dispersal timing, with D1 dispersing the earliest (133 days) and Four dispersing the latest (217 days). I don’t feel like we have enough data to predict who will disperse first, so we will just have to wait and see!

Will D35 and D36 disperse together?
We have put transmitters on just one other pair of siblings – D24 and D25 in 2016. As close as the two were on their territory, they did not disperse together. I believe that the same thing will happen with D35 and D36. Unfortunately, D25 was killed by a car in late September of 2016, so we never got to find out if the eaglets would encounter one another at a congregation spot or on their wintering grounds (usually in or around NE Iowa). We hope that all of our eaglets live long and prosper, and we look forward to learning more from D35 and D36. Keep your talons crossed for them!