Fort St. Vrain Eagles and Blogs

Peek inside a bald eagle egg: 17 days!

This chicken embryo is roughly equivalent to an eaglet at about 13 days. We can see the bony plate around its eyes, long folded limbs, rudimentary feet and 'hands', feather germs, and oversized head. Next up: feathers and scales!

As of this blog post, DNF’s two eggs are 22 and 19 days old. We have a three-day-old egg in Trempealeau and four eggs ranging from 11 days old to two days old at Xcel Energy’s Fort St. Vrain nest. What do embyronic eagles look like as they develop and grow inside their eggs? Dr. Peter Sharpe from the Institute for Wildlife Studies developed a table of bald eagle embryonic development based on work done by Hamburger and Hamilton (1951). While

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FOUR eggs for Ma and Pa FSV!

March 4, 2025: Four eggs for Ma FSV

We saw a once-in-a-nest event at Xcel Energy Fort St. Vrain last night! Ma FSV has been a three-egg layer for most of her laying career, and we had no reason to think this year would be any different until she laid egg #4 at 6:32 MT last night. Congratulations, Ma and Pa – we’re so egg-cited for you! Watch live here: https://www.raptorresource.org/birdcams/xcel-energy-cams/. How common are four-egg nests? Will all the eggs hatch? How likely are any hatchlings to survive?

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March 3, 2025: What are we looking forward to? News and NestFlix from all around our nests!

Mrs. and Mr. T. She's at left, he's at right.

What are we looking forward to this week? Mrs. T still hasn’t laid her first egg yet, which is making me wonder whether we have a new Mr. or Mrs. T! I would be surprised if she didn’t lay this week, especially given the amount of time she’s spent loafing around the nest recently. Go Mr. and Mrs. T! https://www.raptorresource.org/trempealeau-eagles/. The Mississippi Flyway and Castle Rock eyrie cams are both back online. Watch for falcons at Castle Rock – and

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Peek inside a bald eagle egg: 11 days!

Seven day old chicken embryo. It's roughly equivalent to a 12-day old embryonic eagle.

What do embryonic eagles look they look like as they develop and grow inside their eggs? Dr. Peter Sharpe from the Institute for Wildlife Studies developed a table of bald eagle embryonic development based on work done by Hamburger and Hamilton (1951). While not all bald eagle eggs hatch in 35 days, the stages of development look something like this… When we last peeked inside the egg, our embryonic eagle had inner and outer layers, a developing circulatory system, a

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February 25, 2025: A second egg for the Xcel Energy Fort St. Vrain Eagles!

February 26, 2025: A glimpse of the eggs!

And then there were two! Ma FSV laid her second egg at 10:37 PM last night. She and Pa are really on a roll! Ma FSV has a long history of laying third eggs, so look for another one in three or four days. She lays her third egg following a less predictable interval than her second egg, but it generally arrives between 72 and 90 hours after her second. We’re still waiting at Trempealeau. Go Mrs. T!

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Congratulations to Ma and Pa FSV on their first egg of 2025!

February 22, 2025: A first egg for Ma and Pa at the Xcel Energy Fort St. Vrain nest!

Congratulations to Ma and Pa FSV on their first egg of 2025! Like DNF, Ma laid early this year! Since she accepted Pa Jr. back in 2021, she’s laid in early February or the beginning of March: March 4 in 2021, March 3 in 2022, March 2 in 2023, and February 29 in 2024. We thought she might lay early based on her behavior, but it was still a bit of a surprise! Look for egg #2 on February 25

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February 18, 2025: It’s C-C-C-Cold Outside!

February 16, 2025: Pheasant for breakfast

Even by February-in-Iowa standards, it was cold this morning! The coldest post-egg temperature ever recorded in Decorah happened on March 3, 2015, when the mercury dropped to -24F: a record! But we came pretty close today with a recorded temperature of -15F from about 5:00AM through about 7AM this morning. Eagles are well-suited to cold, but we’re still glad to see things warming up! If you’re feeling chilly just watching – I know I am! – grab a warm drink

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Bald Eagles, Eggs and Cold Weather

The eggs are warmed and protected by their parents’ bodies and the insulation beneath and around them.

Cold weather often raises concerns among Bald Eagle watchers. Will their favorite eagles keep their eggs warm and dry in sub-zero temperatures and snow? Eagles don’t have central heating or electric blankets, but they have everything they need to incubate their eggs through the worst a Midwestern winter can throw at them: meticulously built nests that aid incubation and withstand winter’s chill, highly vascularized brood patches that transfer body heat directly to their eggs, and remarkably robust eggs.  In short:

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February 10, 2025: NestFlix and News from Decorah North and Fort St. Vrain!

February 10, 2025: Fly like an eagle! Mr. North shows off his long wings and unparalleled aviation skills

Put up your feet and take a deep breath…it’s time for NestFlix! Today’s Diction-aerie word is ‘eggnant’: a female eagle’s condition immediately prior to laying eggs. Our bald eagle Moms are shifting fat to their brood patches and retaining water as their egg follicles swell and mature. We’re planning to begin egg watch on Friday, but we’ll also be watching for DNF, Mrs. T, and Ma FSV to begin loafing around the nest and ‘practice’ laying as eggs draw nearer!

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