Yes, the day before Easter, Crossroads at Big Creek with hold "that egg thing" again. EGGstravaganza is our annual celebration of eggs, but it is not a hunt. Instead, learners of all ages explore the wonders of bird eggs - the strength, the shape and different variations. Last year the explorations took place outside on lush green grass. But whatever the weather, we will hold the event on Saturday, March 30 at 1:00.
Eggs are significant in the commemorations of both Easter and Passover, so this week many people will be cracking and peeling eggs. Perhaps because they are so familiar, we seldom take the time to appreciate that eggs are structurally beautiful…amazing really.
Consider that the thin shell must be strong enough to protect the embryonic chick from the being squashed by a brooding hen. Understand that egg shape is strong because the blunt end acts rather like a dome, an architectural form constructed to exert an equal thrust in all directions. The mother bird does not break the shell because no single point on the egg supports her entire weight.
But don't assume all bird eggs are shaped like those of domestic chickens. Some wild birds have eggs which are almost round. Other eggs are so tapered at one end that they are almost pointed. The shape of an egg usually is determined by the location and shape of the nest.
Birds that nest in holes tend to have spherical eggs. Spheres are very strong, but they roll. But in a deep cavity nest, rolling eggs have nowhere to go. In contrast, birds that nest on cliffs have very tapered eggs. And that is a good thing. If a cone-shaped egg moves it will roll in a tight circle rather than plummet over the edge.
Birds that nest on bare ground tend to lay tapered eggs. In fact, most shorebirds lay four eggs which they arrange with the pointed ends toward the middle so they fit together like the pieces of a pie. Not only are they less likely to roll away, but fitting close together with very little space in between them, the tapered eggs actually keep each other warm.
A round or tapered egg is much easier to lay than, say, a cube (ouch!) but I was surprised to learn that the blunt end comes out first. It seems that as the mother bird pushes the egg out of her oviduct, she squeezes it with her muscles. On the final push, she squeezes harder, so the not completely hardened shell becomes pointed on one end. Apparently, as a hen ages, her eggs become rounder because her muscles aren't as strong as those of a spring chicken.
Young or mature, humans of all ages are welcome to participate in this EGGciting annual activity Saturday.
Crossroads is a donor-supported learning center located at 2041 Michigan in Sturgeon Bay. While the bridge is out, from the north, just stay on Highway 42/57 and turn east on Michigan Street (or Utah Street if you are going to the Astronomy Campus) From the south, follow the northbound detour through town and cross the highway on Michigan Street. The Collins Learning Center is open 2:00-4:30 daily and during scheduled events. However, the Learning Center will be closed on Easter Sunday and there will be no Community Ski.