It was a blustery day in Decorah today! HM was nearly blown over when she got up to reposition herself, while Mr. North and DNF coped with snow and intruders. What’s going on at the North nest and why isn’t DNF incubating more? We suspect that the intruders are adult female eagles. IF DNF thought they represented a serious threat, she would most likely take on nest-guarding while Mr. North incubated. Male eagles will chase female eagles, but don’t tend to engage in close-quarter fighting, since females are quite a bit larger than males and so more dangerous to them. DNF is incubating as I write this and we’re hopeful that her discouragement – no other eagles allowed! – and warmer weather will have the interlopers moving on.
Pop your feet up and grab a snack – it is time for NestFlix!
Decorah North Eagles
February 22, 2023: Why don’t we migrate? A late February snowstorm dropped a lot of snow in the valley of the Norths! The snow piling up on Mr. North’s back illustrates the insulative properties of feathers: Mr. North wasn’t losing enough heat to melt the snow away from his back. But he eventually gets tired of the drifts and gets up to shake it off!
February 22, 2023: Shake it off! https://youtu.be/Tj5P6-r1G0w. A late February snowstorm dropped a lot of snow in the valley of the Norths! The snow piling up on Mr. North’s back illustrates the insulative properties of feathers: Mr. North wasn’t losing enough heat to melt the snow away from his back. But he eventually gets tired of the drifts and gets up to shake it off! More on eagles and cold weather here: https://www.raptorresource.org/2023/01/27/flashback-blog-how-do-eagles-stay-warm-in-cold-weather/.
We’ve had some questions about the Norths versus HD and HM. How far away are the two nests? The landowner wants the location kept private, but the North nest isn’t that far north of the Decorah area. Having said that, the Decorah nest is much more protected from wind since it lies down in a valley in an area that is lower relative to the surrounding terrain. Topographically speaking, the North nest lies in a shallow wind funnel and is much more exposed to the elements. The difference in weather is a function of terrain more than distance.
February 23, 2023: How deep is the snow? Mr. North protected his egg and kept the snow and ice at bay through the storm!
February 21, 2023: Shift change and egg roll – https://youtu.be/XSeyPw5ipKE. This video gives us a glimpse of the egg and a nice look at a shift change! It opens with Mr. North incubating in a deep, fluffy pile of grass and husks. He gets up at 1:57 and carefully steps around the egg before flying out. DNF comes into the nest at 4:08 and shimmies the egg into place beneath her. The egg is less than a day old at this point, but it already has inside and outside layers and a very rough anterior-to-posterior template in place.
February 21, 2023: Shift change and Mr. North gets his first look at the egg – https://youtu.be/pczs7yausGs. Mr. North greeted egg number one this morning at about 6:04 AM! DNF was drowsily incubating when he began peal calling. She vocalized back and the two swapped places for Mr. North’s first shift of 2023. Look at his balled, loosely-held feet as he carefully steps into the nest. He and DNF’s months-long nest prep created a perfect nursery, but he is still careful not to step on, pierce, or unexpectedly jostle his egg.
February 23, 2023: Mr. North pulls the blankets up! Cornhusks can be easily adjusted as needed: pulled up to prevent heat loss, moved to cope with wind, or thrown back to cool things down!
I love watching eagle Dads interact with their eggs. Experienced Dads know exactly what do to – how to step into the nest, how to gently shimmy the egg beneath them, and how to control temperature and humidity. But while eagles will instinctively incubate eggs and egg-shaped things, experience is learned. First-time Dads sometimes seem hesitant, especially the first time they approach their egg. A two egg clutch is relatively easy to manage, but a new Dad can struggle with getting three eggs beneath him. We’re looking forward to seeing how HD and HM do in Decorah – and very glad that Mr. North and DNF are old pros when it comes to eggs and eaglets!
February 20, 2023: DNF lays her first egg of the season – https://youtu.be/t0-hpXl2Vjc. DNF is tipped forward in the nest in her final moments of egg labor. A sphincter muscle rotates DNF’s egg so it enters her cloaca pointy-end first. Her powerful vaginal muscles and full-body contractions eject the egg through her cloaca and into the waiting egg cup.
Do eagles feel pain when they labor? At one point, researchers believed that their vagina and cloaca lacked nerve endings. But even if they did – and I’m not sure this is correct, since feeling is required for somatic feedback and response – her full-body contractions are almost certainly uncomfortable. From fertilization on, egg laying is a labor-intensive process. DNF spent nearly an hour recovering from labor before settling down on her egg.
Decorah Eagles
February 23, 2023: Handsome HD seems more than ready for eggs! First-time eagle dads can sometimes appear a little hesitant or reluctant when it comes to incubation, but it looks like HD is ready to go!
February 23, 2023: HM finds nestover fish and lies in the nest – https://youtu.be/t7parCgU4oM. It’s a good thing that HD stocked the pantree with a frozen fish earlier today! At 33 seconds, we see HM in the nest. She quickly finds the fishstick and wrenches it apart, devouring little tidbits as she pulls apart the frozen treat. Lunch done, it is time to work on the nest bowl! She settles into the nest, scrapes a bit, and begins shredding and arranging the cornstalk roses that HD so thoughtfully delivered. I especially enjoyed the overhead view we get at 8:50 – HM’s rich brown feathers look beautiful against the golden husks, stalks, and grasses!
February 23, 2023: Sometimes wind sneaks around behind you!
How does an aerodynamic animal keep from being blown out of the nest by the wind? Eagles raise the rails, lower the floor, hunker down in the nest, and usually face into the wind. But sometimes the wind switches direction! Watch in the eighth minute to see HM hunch down, flatten up, and eventually reposition herself as the wind comes at her back, blows up her tailfeathers, and nearly knocks her over when she stands up.
February 23, 2023: HD working on the nest – https://youtu.be/45BTsDHwJbc. The video opens with HD perched near N1. At 16 seconds, he floats into the nest and tests it. He’s laying fairly flat, but the wind still ruffles his feathers as he digs and moves soft materials around. Check the video at 3:43 for a great look at how nicely he and HM have arranged nesting materials. HD gets up at 4:30 and begins raising the rails. Higher sides will help protect he and HM from the wind!
The Raptor Resource Project