17 Extraordinary Bird Egg Facts

Updated: Jan. 12, 2024

Learn interesting egg facts, including what bird lays pink eggs, what bird lays eggs in another bird's nest and why bird eggs aren't round.

Oldest Egg Laying Bird

Laysan Albatross (phoebastria Immutabilis), how long do birds liveENRIQUE AGUIRRE AVES/GETTY IMAGES
Laysan albatrosses

This one of our egg facts might be the most amazing! Wisdom, a 70-year-old Laysan albatross and the oldest banded wild bird on Earth, hatched an egg in 2021 with the help of her mate, Akeakamai.

Learn how to identify bird eggs by color and size.

Bird Eggs Are Similar to Dinosaur Eggs

Robin eggsCourtesy Lesley Rutter
Blue American robin eggs

One of the most interesting bird egg facts that despite the broad variety in colors and markings displayed by bird eggs, just two pigments are responsible for staining the shells of all known species of living and extinct birds, including dinosaurs.

Birds in Cold Weather Lay Colorful Eggs

White, Brown And Green Eggseyewave/Getty Images
Brown, white and green eggs

Recent research shows two egg colors—reddish brown and green—are determined partly by temperature. Eggs with darker colors exist more in colder areas because they absorb heat better.

Learn all about robin nests and eggs.

Meadowlark Nests Are Unique Egg Domes

Meadowlark,nestMika Skye/Shutterstock
Meadowlark nest

Female western meadowlarks construct dome-shaped structures on the ground for their nests before laying five to six eggs inside.

Get ready for baby birds with these tips for nesting season.

Emperor Penguin Dads Help Care for Eggs

Antarctica, Snow Hill Island, emperor penguin with chick on icePaul Souders/Getty Images
Emperor penguins

Does this make them some of the best bird dads? Emperor penguin dads have a special flap to keep their eggs warm, incubating them for about 65 days.

Chicken Eggshells Are Porous

Red Sussex Hen Looking At EggPIER/Getty Images

Chicken eggshells have as many as 17,000 pores, which allow air and moisture to pass through.

Learn how to recognize northern cardinal eggs.

Cowbirds Lay Eggs in Other Birds’ Nests

egg facts Cowbird Egg Among Bluebird Eggs in a NestLois_McCleary/Getty Images
Cowbird egg in a clutch of eastern bluebird eggs

Female brown-headed cowbirds deposit their eggs in other birds’ nests. Cowbird eggs have been found in nests of more than 220 other species. Eggshell colors serve to signal the identity of each egg. For example, the parasitic cowbird egg sticks out in the nest among an American robin’s blue eggs. Typically, the robin recognizes the cowbird egg and tosses it out.

Do birds reuse their nests?

How Strong Are Eggshells?

sandhill crane eggsCourtesy Rissy Medlin
Sandhill crane nest, eggs and baby

Large birds sit on eggs, too, so their eggs have to be strong enough to withstand the weight. It takes about 26 pounds of pressure to break a swan egg. Similarly to corals and seashells, eggshells have a lot of calcium carbonate in them. It’s estimated that 95% of an eggshell is composed of this material.

Learn when bluebirds nest and lay eggs.

How Much Does an Ostrich Egg Weigh?

High Angle View Of Ostrich With Eggs On FieldKasper Nymann / EyeEm/Getty Images
Ostrich female protecting the big eggs in the rain

Here’s another one of the most amazing egg facts: a single ostrich egg can weigh as much as 5 pounds.

Find out what to do if you find a bird nest with eggs or a baby bird.

What Kind of Bird Lays Dozens of Eggs in a Nest?

egg facts Male and female wood duckEEI_Tony/Getty Images
Male and female wood duck on a nest box

A wood duck can lay up to 15 eggs in one nesting attempt, but a single nest may have as many as 40 eggs from more than one female. Interestingly, according to one study, less than 1% of waterfowl eggs contain twins.

Hummingbird Eggs Are Tiny

Hummingbird nestCourtesy Marion Ball
A peek inside a hummingbird nest

Rufous hummingbird eggs are 1/2 inch long and fit snugly in the 2-inch-wide nest, which usually holds two eggs.

Here’s everything you need to know about hummingbird nests.

How Long Does Egg Laying Take?

bird nest with eggs pat morton, egg facts, bird eggs in nestCourtesy Pat Morton
Female birds don’t lay all eggs on the same day.

Most songbirds lay one egg per day until their clutch is complete, and it takes most female birds at least one day to form an egg.

Learn more about mourning dove eggs and baby mourning doves.

What Bird Lays Pink Eggs?

tree swallow bird houseCourtesy Carol Pedersen
Tree swallow family in a birdhouse

Pale pink at first, tree swallow eggs turn white within four days. Learn more about the different types of swallow bird nests.

Do Birds Peep Before Hatching?

Migratory birds in Colorado. American White Pelican in flight.Gary Gray/Getty Images
American white pelican

American white pelicans lay two eggs per clutch. The young are able to squawk from inside their eggs if they’re too hot or cold.

You need to see these super cute photos of baby birds.

Why Are Bird Eggs Not Round?

egg facts, Killdeer Standing Over Nest With EggsJoe McDonald/Getty Images
Killdeer standing over nest with eggs

An egg that is pear-shaped easily settles within the nest, or even on bare ground if the parents opt not to build a nest.

Learn all about the different kinds of bird nests and how to spot them.

Do Eggshells Help Baby Birds?

bluebird eggs and hatchlingCourtesy Heather Parker
Newly hatched baby bluebird and eggshell

The eggshell serves as a calcium supply for the growing embryo. As the embryo matures, the shell slowly becomes thinner and the hatchling has an easier time breaking through.

Can you move a bird nest?

California Condors Don’t Lay Many Eggs

California Condor sitting on a rockWeili Li/Getty Images
The California condor is the largest bird in North America. They are endangered species.

This one of our egg facts will surprise you. Endangered California condors wait until they’re 6 to 8 years old to find mates, then produce only one egg every one to two years.

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