We have your news and nestflix from Decorah and Decorah North! In Decorah, HM laid egg #2, HD learned how to incubate eggs and airdropped breakfish on HM, and both eagles were annoyed by a juvenile intruder. Go get your own food! At Decorah North, DNF and Mr. North continued to cope with intruders and a squirrel picked up but did not bite through the egg. Sometimes I pick favorites, but I enjoyed every one of these videos!
Thanks so much to our camera operators and videomakers for finding and sharing such special moments, and to all of you for watching, learning, and especially for caring! Want to test your eagle egg knowledge? Check out this week’s quiz! https://www.raptorresource.org/classroom/weekly-quiz/
Decorah Eagles
March 1, 2023: A subadult eagle on HM and HD’s territory. Juveniles and subadults are not as dangerous as full adults. HD and HM don’t like them, but don’t guard as diligently against them.
February 28, 2023: Juvie flies over N1, lands above the Y – https://youtu.be/YAUyd6KhHTo. HM (I think) is sitting on the Y. A juvenile flies in and lands on the branch above her at seven seconds. She and HD both issue warning vocalizations, but don’t attack it or attempt to run it off. At 1:05, the warning vocalizations cease. At 1:11, the juvenile flies off. That we can tell, neither adult gives chase – although a member of the neighborhood crow watch does!
February 28, 2023: HD gathers grass for the nest.
February 28, 2023: HD gathers grass for the nest – https://youtu.be/ziuRI8vyxi8. Where do eagles get grass for their nests? In this video, HD pulls it from the riverbank! He grabs a clump in his powerful talons and jump flaps up several times, finally wresting it loose and flying away at 1:10. He delivers it at 1:45 and puts it off to the side of the egg cup – extra material for battening down the hatches in case of rain or snow!
March 1, 2023: HD’s tailfeathers. Note the brown spots – a great ID marker when we can see his tail.
February 26, 2023: Nice look at the egg, egg roll – https://youtu.be/EdRbAAMSFeA. HD is incubating in his warm and very fluffy nest! He gets up at 54 seconds and carefully beak rolls the egg as he attempts to tuck it beneath him. After attempt one fails, he fiddles with some material and tries again at 1:50. Success! He shimmies over the egg and gets it into place.
We’ve got another nice look at shimmying here: https://youtu.be/NNihXc4mEFI. Go to 7:11 for a wonderful look at HD’s egg care and the wonderful snug egg cup. Everything has to be positioned just right (including his feet, the husks and grass, and an intruding stick) before he settles over his egg. It’s wonderful to see his egg skills improving!
February 25, 2023: HD drops off a fish gift and close-up of the egg – https://youtu.be/Z-sjYqBUngM. HD flies into the nest with breakfish but loses control before he lands, dropping it on HM! Slow the video down or stop it at seven seconds for a great look at the flying fish. It bounces off her back and slides down into the egg cup. HD hovers over her, but she has the fish and the egg, and she isn’t moving! He expertly launches himself into the wind and flies out at 3:18 to stand sentinel on the Y.
HM gets up at 5:27 and starts looking the egg/fish situation over at 6:12. How to get the egg safely away from the fish so she can grab it and eagle it down? She tries to insert her beak between the fish and the egg, but that doesn’t work. Next she takes teeny nibbles of the fish – eggcellent eaglet prep, but not an especially efficient way to eat a fish. At 7:15 she carefully grabs the fish’s head and gently pulls it away from the egg and out of the egg cup. We get a nice look at the egg and she finally gets breakfish!
Decorah North Eagles
February 28, 2023: Like water off an eagle’s back!
Intruders continue to roil activity at the North nest. RRP master bander Dave Kester checked it out on February 27 and reported three adult eagles quite close to the north nest. As we suspected, DNF is spending most of her time guarding the nest and chasing the strangers away. Unfortunately, we’re getting a really excellent look at the ways in which eagle populations limit themselves, something we’ll be writing more about.
Why has DNF been spending so much time away from her eggs? Broodiness is caused by hormonal changes. After egg number one, testosterone and progesterone rapidly decrease while prolactin, a hormone that induces incubation and brood patch swelling, rapidly increases. The intruders might be boosting the production of hormones that prohibit or interfere with broodiness.
Will the egg survive? We weren’t too concerned about the incubation patterns we saw on February 24, since we’ve seen eagles spend fairly long periods of time off newly laid eggs before. But the intruders are upsetting things and a fox squirrel attempted to eat the lone egg on February 28 while DNF and Mr. North were away. It wasn’t successful, but we have no idea whether the egg is still viable. For now, we’ll continue to watch the nest and document activity in the valley of the Norths. Thank you for watching with us. Life in a wild nest isn’t always easy.
February 28, 2023: A squirrel in the North nest. It did not bite through the egg.
February 28, 2023: Squirrel finds the egg in the nestbowl – https://youtu.be/nj3sN99S32g. Exactly what the title says. DNF and Mr. North are away dealing with the intruders. A fox squirrel enters the nest and starts foraging. It finds the egg at 33 seconds, lifts it up into its arms, and attempts to bite it. The squirrel’s gape is too small and the egg is too strong, so it does not penetrate the egg. It quickly loses interest and places the egg back into the nest before searching for something easier to eat! Take a look at 2:45 to see the unbroken egg.
The strongest part of an ovoid is at its narrow tip. The sharper the curve of an ovoid, the stronger and more rigid it is at its tip. An egg’s ovoid shape helps it to resist crushing – try grabbing an egg and squeezing it in your hand to experiment – and the squirrel was trying to break in near the egg’s strongest point. Fortunately, its gape and jaw strength weren’t up to the job!
February 28, 2023: Like water off an eagle’s back.
February 27, 2023: DNF comes to the North Nest: https://youtu.be/ShEXSTDXclk. DNF is a magnificent female eagle and from her perspective, she’s doing everything she can to keep her egg safe. The video opens with her perched on the ladder branch. At 56 seconds we get a closer look at her, including her head, rich brown feathers, and toes. Although she moves to the nest at 6:22, she does not cover the egg.
The Raptor Resource Project