Tag Archives: Eggs

Finally, an egg at N3!

March 28, 2022: D2 in N3. Photo by Mark Worcester.

What has been going on with Mom and DM2 this year? RRP staff and volunteers have been monitoring Mom and DM2 at N3 and the hatchery, and we have a pretty good record of their whereabouts with boots-on-the-ground observations and appearances on the hatchery cams. We have documented her standing in the nest for long periods of time, but she didn’t begin incubating until sometime between Robin’s observations on Sunday, March 20 and Dave Kester’s observations on the morning of

Egg Colors and Shapes

The Chicago Peregrine Program inspired me to write a quick blog on the colors and shapes of eggs. Bald eagles have white eggs, peregrine falcons have eggs that range from light cream through brick red, and red-tailed hawks have pale eggs that are lightly splotched with brown. How and why do the birds we watch lay differently-colored and shaped eggs? In general, female birds inherit egg colors and patterns from their female parents. Egg-shell is made primarily of calcium carbonate,

Peek inside a bald eagle egg: 11 days!

Chicken embryos roughly 25% of the way to hatch

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… What happens between the third and the 11th day? When we last touched on the topic, our embryonic eagle had

Peek inside a bald eagle egg: 4 days!

An embryonic bird at 33 hours

As of this writing, we’re still waiting for eggs at Fort St. Vrain. The first Decorah North egg is seven days old and the second is four days old. What do embryonic eagles look like as they grow and develop 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

What Makes Bald Eagles Incubate?

February 21, 2022: North Nestoration Follies!

I loved watching Mr. North incubate eggs through today‚Äôs snowy weather. He turned his head out of the wind, closed his eyes to protect them from the blowing snow, and fell asleep as the nest rocked gently back and forth. What makes normally active birds like hawks, falcons, and eagles spend so much time sitting on eggs? Hormones, egg production, and broodiness As daylight length increases, birds’ gonads swell. Both sexes produce testosterone, although male birds produce more than female

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