We have extremely cool news from Xcel Energy’s Fort St. Vrain plant! Donna Young and Elfruler got Ma FSV’s band number! She is 22-year-old 0629-44094, a single eaglet from a still-active nest about 45 miles east of the Fort St. Vrain site.
April 18, 2024: 0629-44094, aka Ma FSV. She is 22 years old and fledged from a still active nest about 45 miles east of this one.
Why is it important to get band numbers? In this case, it gave us some crucial information about Ma’s longevity and nest of origin. Eagles exhibit philopatry: the tendency of an animal to remain in or return to the area of its birth – something Ma embodied by nesting just 45 miles away from her nest of origin. It also reinforces the importance of keeping reproductive records, since the site’s production history suggested that a new eagle – Ma FSV – replaced original Ma back in 2007.
What made us think that? In 2006, the first egg arrived on February 17th. But in 2007, it arrived on March 3rd, two full weeks later. Egg-laying wanders a bit, but it’s pretty unusual for it to change that much in an established layer. Ma would have been almost five years old in February/March of 2007: the same age that Mom Decorah was when she started nesting with Dad back in 2008. It’s not uncommon for new mates to push egg-laying back, especially when they are young adults and first-time layers, which is what we were most likely seeing here.
April 18, 2024: Pa Jr. feeds his young.
Elfruler and Donna also got Pa Jr’s band number! Elfruler wrote: “He was captured and banded by a wildlife biologist working with the Denver International Airport as part of their Wildlife Management Plan to mitigate threats to wildlife and aircraft. Their practice is to release a captured raptor about 40-50 miles from the airport. He first appeared at the Fort St. Vrain nest in fall of 2020, but we are in the dark about his age or nest of origin. The best we can say is that he was at least five years old in 2020.“
A ton of thanks to Donna, Elfruler, and the Fort St. Vrain group for getting and sharing this information with us! Curious about eagles, fertility, and menopause? Us humans are pretty unique, since very few species have prolonged post-reproductive lifespans. More here: https://www.raptorresource.org/2021/02/25/has-ma-fsv-entered-menopause-no/.
The Raptor Resource Project