Tag Archives: Weather

Eggs and cold weather

04/18/18: Mrs. North incubates through the snowstorm

This blog was first published on Wednesday, February 26, 2014. It has been updated to reflect Mom’s new mate and includes some information about the Fort St. Vrain eagles as well. Everyone was worried about the eggs in Decorah back in 2014. Iowa was facing a polar vortex while Mom was laying and incubating eggs. While there have been other cold years, 2014 was one for the record books, with windchills of -50F when Mom laid egg #2. Given that 2019

Nest chronology: Egg timing!

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 in 2018? 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

How do eagles stay warm in cold weather?

04/18/18: Mrs. North incubates through the snowstorm

Iowa bald eagles nest in surprisingly cold weather. How do they keep themselves and their eggs warm? Unique body features and changes in physiology and behavior help bald eagles maximize energy gain, minimize energy loss, and incubate eggs in cold temperatures. To maximize gain, eagles forage in groups, gorge food, and increase the assimilation of ingested food energy. To minimize loss, they become sedentary, seek protective microclimates, and reduce night-time body temperature. Put simply, eagles keep warm by using the