Put your feet up and chill with Nestflix from Decorah, the Flyway, and Great Spirit Bluff! In Decorah, Mom and DM2 copulate and we get some fantastic looks at Mom’s feathers. On the Flyway, a raccoon and multi-age group of eagles forage for food. Ice is beginning to melt and uncovering the concealed bodies of fish – an excellent food source for hungry mammals and bald eagles after winter’s lean season!
So what’s going on a Great Spirit Bluff? Michelle isn’t back, but Newman is courting and copulating with an unbanded female falcon. Something similar happened last year and Michelle simply drove the interloper off when she arrived. Since the two copulated, does that mean this female will lay eggs if she’s driven off? Not necessarily. It takes a lot of work for male birds to bring female birds into condition – they need to copulate regularly and bring plenty of food before their mates begin ovulating. If Michelle is going to return from migration, she should do so within the next week.
Before we get into the ‘Flix – we have a new website with free lesson plans for teachers. Check it out here – this website is public and open to everyone: https://raptorresource.education/
March 6, 2020: Romantic evening on N2B – https://youtu.be/t46f2mjpv7o. This video starts with spectacular close-ups of DM2. He gets up at 1:24 and does a little eagle yoga before getting off the eggs (note that they appear to be in a line). While we don’t see her, I think that Mom comes in at 1:37’ish – listen for the wing flaps! She begins vocalizing, signaling receptivity by her vocalizations and by leaning forward. DM2 is immediately interested. He walks up up to her, also vocalizing, and the two copulate. DM2 continues vocalizing for a short period. Mom flies down into the nest and rolls the eggs into her signature triangle before settling over them.
March 6, 2020: Mom close-ups – https://youtu.be/hOXUBzzt1FE. Six minutes and 41 seconds of Mom on a mild day in Decorah-dise! If you’ve ever wondered how Mom – or any other bird – stays dry through rain and snow showers, check out the 4th minute. We get an excellent look at how her feathers overlap one another and zip together, creating a waterproof coating that repels everything but the very worst weather! Bits of adult down are visible here and there. Prolactin, which is produced in the bodies of incubating eagles, is associated with molt and gonadal regression, and incubation – a period of relative inactivity for both eagles, if a little more so for Mom – is a great time for molt.
Great Spirit Bluff
March 6, 2020: Newman mates with unbanded female – https://youtu.be/3Cumx-X8hEU. Look for the similarities and differences between peregrine falcons and bald eagles! The unbanded female signals her receptivity by chupping, tilting forward, and flattening her back. Newman flies in for an acrobatic copulation. See how his feet are curled to avoid hurting her?
It was commonly believed that peregrine falcons (and eagles) were monogamous. The reality is more complicated. Falcons are deeply bound to their territory and tend to be one-mate birds. However, they will take new mates if their former or established mate is absent – especially during the spring, when gonads are swelling and hormones are flowing.
March 5, 2020: Raccoon, Big Fish and Eagles – https://youtu.be/2JYY84oxA4c. The ice is beginning to go out and the Flway is getting busy again. A racoon takes advantage of the warmer weather to forage for fish on the ice. At 8:22, the camera operator finds a multi-age group of eagles engaged in a food fight. The oldest eagle has control of the food, but the subadults very badly want in on it! What is it? Check 12:47 and you’ll see that it’s a large fish, frozen in the ice! This is a great time of the year for animals like raccoons and eagles to feast on fish and other carcasses thawing out of ice and snow.
Odds and Ends
How is climate change impacting birds? We know that our falcons are laying eggs earlier than they used to: https://www.raptorresource.org/pdf/AverageNesting.pdf. A new paper finds that the phenology of nocturnal avian migration has shifted at the continental scale: https://www.nature.com/articles/s41558-019-0648-9.
Trying to keep up with the migration forecast? birdcast.info is your website! Since spring migration occurs so quickly, I highly recommend using this tool to help optimize your Flyway watching: https://birdcast.info/. Ice-out is coming!