We have your #SundaySweets, including videos from the Decorah, Decorah North, and Xcel Fort St. Vrain eagles, a link to more information on molt (the feathers are flying!), and musings on symmetry. We hope you enjoy these videos as much as we did. Thanks so much to our camera operators and videomakers for finding and sharing such special moments, and to you for watching, sharing, learning, and caring! <3
Decorah Eagles
We know that bald eagles appear to prepare sticks for pruning by stripping them and gnawing on them. But what is their criteria for choosing sticks? Ease of breakage? Proximity to the nest? Clearing flyways and sightlines? Symmetry? The mind boggles!
12/14/19: Older SA replaces younger SA on the maple – https://youtu.be/-n4YSj_ecPc. We always wonder if the subadult eagles we see are Mom and Dad’s offspring (DM2’s offspring will be subadults next fall). We know that eagles are very social/gregarious off their breeding grounds and can be a little social on them, depending on the time of the year and how close visitors are to the nest. I like the idea that this could be Mom and Dad’s offspring, but I also like the thought that young eagles could be attracted to any nest, anywhere, and that adult eagles would tolerate them as long as they didn’t fly into the nest or occupy favorite perches. #EagleFamily
12/13/19: More furniture for the Decorah Eagles – https://youtu.be/mZRp2ADSXAI. A nursery can never have too much furniture! I liked the whole video, but check out 8:13, when DM2 starts struggling with the large stick he lumberjacked in on December 12. At 8:37, he puts his talons and beak into it as he tries to manuever it into just the right spot! At 9:16, he finally gets it and drags it across the nest! I enjoyed the symmetry of the two large sticks starting in the 9th minute. We know that bald eagles – especially male bald eagles, at least at our nests – have a serious stick obsession! They must have something in mind: a framework, a plan, an understanding – to guide them in their sticky decisions. Perhaps symmetry is part of the framework? He moves the stick again in the 11th minute (still not just right!) and we get great looks at the nest at 12:01 and 15:25.
A study of symmetry recognition in pigeons indicates that pigeons are capable of categorizing visual patterns into symmetric and asymmetric classes. Symmetry recognition in birds could help them detect camoflauge when foraging, recognize partners, assess potential partners…and architect sturdy nests! Does symmetry also inform stick grooming and selection?
Decorah North Eagles
December 15, 2019: Mr. North
12/14/19: Some highlights of the day – https://youtu.be/PPgDWF4iBTc. Watch the whole video, or go to 7:39 for some great closeups! We get a very nice look at feathers at 9:50. See those pale feathers? They are older and will be molted out – a topic that touches on symmetry (molt is often symmetrical) and hormones. More on molt here: https://www.raptorresource.org/2019/05/19/what-are-feathers-what-is-molt/. I also loved the dual perching and preening that started around 18:20 as Mr. North (back) and DNF (front) engaged in a little side-by-side self-care. At 37:15, we get a nice view of the Valley of the Norths and at 40:08 we get a great fly-in by DNF as she adds more furniture to the nest! Check 44:24 for a really nice look at the nest, with this year’s rails and bowl piled on top of the super-structure that forms the lower nest.
Xcel FSV Eagles
12/13/19: Nest activity – https://youtu.be/7WG9eva-lDc. This isn’t quite mating, but I would file it in the bonding catgory. I think the eagle at left is the male, but I would love comments and feedback from all watchers…especially Vrainers! Whatever is going on, things look good for production at the FSV nest this year.
The Raptor Resource Project