Decorah Bald Eagles
Decorah North Bald Eagles
GSB Peregrine Falcons
Eagle Valley Bald Eagles
Xcel Energy Birds of Prey
Great River Energy Falcons
Dairyland Power Falcons
Additional Falcon Cams
Marshy Point Ospreys
Newsletters, Reports, Papers & Videos
The Robert Anderson Memorial Scholarship Fund
Remembering Bob Anderson
A Field Guide To Birds Around Our Nests
Bald Eagles: Egg to Week One!
Know Your Eagles: Quiz 1
Know your Eagles: Quiz 2
Mom or Dad?
What do you know about bald eagle eggs?
Hunt and Fish Lead Free
Dealing with Dead or Injured Birds
Bird Band Look-Up
Make a Donation
Contribute to the Robert Anderson Memorial Scholarship
What do you know about bald eagle eggs?
Question #1: How long does it take a bald eagle egg to hatch after laying?
Sorry! It takes 35 to 39 days for a bald eagle egg to hatch after Mom lays it!
Question #2: What is the optimal temperature for egg incubation?
About 105 degrees
About 90 degrees
About 99 degrees
About 60 degrees
The optimal temperature for bald eagle egg incubation is about 99 degrees. Since Mom and Dad have body temperatures of about 105 degrees, they have heat to spare!
Question #3: On average, bald eagle eggs are:
About 2.9 inches long and 2.2 inches wide.
About 6 inches long and 5 inches wide.
About 1.1 inches long and .8 inches wide.
About 1.5 inches long and 1.2 inches wide.
Sorry! Bald eagle eggs are about 2.9 inches long and 2.2 inches wide. Learn more about eggs here:
Question #4: Where does the calcium for a bald eagle’s egg come from?
Its diet and its skeleton
The calcium for Mom's eggshell comes from her diet and her skeleton. Her medullary bone acts as a reservoir for the supply of eggshell calcium if enough isn't available in her bloodstream during calcium deposition! While Mom eats bone, many birds eat snail shells to help supply them with the calcium they need to build their own bones and lay healthy eggs.
Question #5: How long does it take a female bald eagle to build and lay an egg?
About 25 hours
About 5 days
About 10 days
About 48 hours
Once Mom has deposited a fertilized yolk in her oviduct, it takes about 48 hours for her to build and lay an egg! The egg is fertilized at the infundibulum, gets most of its albumen in the magnum, gets its inner and outer membranes in the isthmus, and is covered with calcium in the uterus or egg shell gland.
Question #6: What is the window of time for egg yolk fertilization to occur?
Dad's sperm have just 15 minutes to fertilize Mom's yolk before it seals over and fertilization is no longer possible! Sperm and yolk meet at the top of the oviduct in the infundibulum, a special organ where fertilization occurs.
Question #7: When does an embryonic eagle’s heart begin beating?
2 hours after an egg is laid
24 hours after an egg is laid
72 hours after an egg is laid
10 days after an egg is laid
Sorry: a bald eagle's heart begins to beat inside the shell roughly 72 hours after an egg is fertilized. Think of that the next time you see a recently laid egg!
Question #8: How does an embryonic bald eagle get oxygen in the egg?
It breathes through its lungs
A special membrane provides oxygen
The egg yolk provides oxygen
The albumen (egg white) provides oxygen
The embryo is attached to the chorioallantoic membrane or allantois - a special membrane that exchanges gases through the porous eggshell. This membrane acts as a
respiratory organ, gets minerals from the shell, and handles waste!
Question #9: True or false: an egg will die if it isn’t constantly incubated!
True! Eggs die of cold very quickly and constantly need to be kept warm.
False! Eggs need to be incubated at the correct temperature, but they don't need to be covered all the time!
Eggs can die of cold, but they can also die of heat. Mom and Dad will get off the eggs to give them a chance to cool down, to let them air out, and to reduce humidity.
Question #10: What part of the egg becomes the eaglet?
The egg white (albumen)
A special membrane
None of the above
All of the above
None of the above! The union of sperm and egg forms a blastodisc, or germinal disc. As cells dive and reproduce, they build the eaglet's body. The egg white, egg yolk, and various membranes all exist to support the embryonic eaglet.
Question #11: What color is a bald eagle’s egg?
A bald eagle lays white eggs!
Congratulations, you passed!
I'm sorry but you did not achieve the required score.