KATHLEEN KUDLINSKI: They are incredible after all - eggs (video)

Editor's note: This column ran a number of years ago, but was requested again by several readers. Eggs seemed to be everywhere this week. Stores offered chocolate eggs, caramel, cream and hollow sugar ones with tiny scenes tucked inside. One candy company makes spring treats with a yellow "yoke" inside a cream "white" wrapped inside a chocolate "shell." It is a marvel of candy engineering, but it can't compare with the real thing.

Eggs are intricate wonders, though we usually don't even notice as we drop them into a skillet in the morning. Our giant hands can crack eggshells easily on the edge of a frypan. Cracking doesn't happen often in nature. Those shells are incredibly strong against more natural dangers. Put a whole egg in your palm with the narrow end toward your fingertips. Make a fist over it and squeeze. Hard. Harder. You probably cannot break the shell at all. Its strength comes from both the substance of the shell and its shape.

Not all eggs are shaped the same. Birds that nest on cliffs lay very pointy eggs. If they roll, these eggs won't fall off the cliff. They roll in tight little circles and come right back home again. Eggs laid into a snug little nest have one end only slightly smaller than the other. That shape makes the best use of space.


Chickadees, woodpeckers and other birds that nest in cavities in trees or birdhouses never worry about their eggs rolling up and falling out of the "front door." Their eggs are almost round. Owl eggs are as round as -- and look like -- Ping-Pong balls.

These cavity-nesters don't have to worry about camouflaging their eggs, either. Their eggs are all white or very pale colors. Birds that nest down on the ground have to lay streaked or splotched eggs, so the helpless nestful is nearly impossible for predators to see. Some eggs are tinted as they are formed inside the mother's body. Other hues, speckles and streaks are actually added as the egg is being laid.

No matter the color, all eggs are built the same inside. Under the porous shell are two thin skins. One of these membranes hugs the inside of the shell. The other surrounds the egg's white. They let necessary air inside, but keep the contents from drying out.

The egg white provides moisture and cushioning to the developing chick. The yolk is its food source. Yokes aren't just floating loose in there. They're tied firmly in place, centered within the shell, by a gooey, twisty cord called the chalaza. That's the thick wad of egg white you can see when you break a raw egg on a plate.

The size of the egg doesn't matter. Hummingbird eggs have the same structures inside as ostrich eggs. Timing doesn't matter, either. Our local nesting owl's eggs are already hatching. Goldfinches won't produce eggs until late July. Every egg is a beautiful system tested and perfected over hundreds of millions of years. Countless eggs will fill uncountable nests this season. Cartons of hen's eggs fill the coolers at grocery stores. These natural wonders are so common it is easy to forget that each one is a miracle.

EMAIL OR WRITEDear Readers, I can't count the number of calls I've had for a collection of my nature essays. So after having 40 of my children's books published, I'm finally doing an "adult" book based on these columns, and I need your help. Email or drop me a note if you have a little time to answer a few questions. (This is called "crowd-sourcing" in today's tech-speak, but to me it feels more like gathering a group of friends.) I'll send you a quick sheet on how to see more animals outdoors, and I'll acknowledge your help by name in the final book. Thanking you in advance.

-- K.K.

Enjoy Guilford naturalist and children's book author Kathleen Kudlinski's daily nature notes and thoughts at her Pondside Place blog, www.kathleenkudlinski.com. Email her at Kathkud@aol.com or write to her c/o the Register, 40 Sargent Drive New Haven, 06511.