Tag Archives: Eggs

Do bald eagles delay incubation?

February 14, 2019: FSV

This blog was first published on Tuesday, March 29, 2016. It has been updated to reflect new knowledge and events. Do bald eagles delay incubation? It wasn’t an a question we’ve thought about much, since bald eagles in Iowa usually lay eggs in temperatures under – sometimes well under – freezing! However, 2016 was quite a bit warmer, and the eagles in Decorah and Fort St. Vrain seemed to spend more time off the first two eggs than we are used

February 13, 2019: 1st egg for the FSV eagles!

Congratulations to Xcel Energy’s Fort St. Vrain eagles on their first egg of the year! It arrived at 8:40PM MT on February 13th – a perfect Valentines Day treat for all of us today! This video by Elfruler shows the entire event: https://youtu.be/koO15X2PDMU. I love the new egg and the ducks in the background. This seems like a good time to revisit the whole subject of incubation: https://raptorresource.blogspot.com/2016/03/do-bald-eagles-delay-incubation.html. This blog was first published on Tuesday, March 16.

How long does it take a bald eagle to lay an egg?

An egg in cross section, modified from Romanoff and Romanoff, 1949

We’ve talked about how long it takes bald eagle eggs to hatch after they are laid (an average of 38 days from first egg to first hatch in Decorah), how long hatch takes once pip starts (it can take upwards of 24 hours), and how long it takes Mom to lay each egg (she usually lays the second egg about two to three days after the first, and the third egg roughly four days after the second egg). But how

Will Mom and DNF lay eggs?

An image of eggs

Will Mom and DNF lay eggs? When will they lay eggs? Will those eggs be fertile? A lot of watchers have egglets and eaglets on their minds! The short answers: We believe that Mom Decorah and DNF (the Decorah North Female) will lay eggs based on what we’re seeing at their nests. They are both bonded with mates who are meeting their physical and psychological needs, including meal-sharing, mutual nestwork, nest bowl preparation, territorial defense, courtship, and copulation. While we worry,

Flashback Blog: Why did Mom and Dad lay eggs later this year?

Second egg for the Decorah Eagles!

This  blog was originally published on Tuesday, March 20, 2018, to answer questions about egg-timing. It discusses the correlation between new mates, temperature, humidity, and egg-timing.  We’ve been getting questions about egg timing. Why did Mom and Dad lay eggs later this year? Overall, avian egg-timing in the temperate zone is heavily regulated by the light cycle. As the days begin to lengthen, birds’ gonads swell and produce sex hormones. Around the end of January, our bald eagle pairs switch from

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