In the book What It's Like to Be a Bird: From Flying to Nesting, Eating to Singing--What Birds Are Doing, and Why, David Allen Sibley writes: “If you find a broken eggshell on the ground, the shape of the pieces can give you some information about what happened. If an egg hatches normally, the chick chips away a ring around the widest part of the egg and the egg separates into two halves. The parents then carry the eggshells from the nest and scatter them some distance away. An eggshell cut straight across in this way is likely to be the result of successful hatching nearby. Eggshells in smaller pieces, fragmented or crushed, could be the result of an accident or predation. Given the opportunity, many species of birds and small mammals will eat the contents of an egg and leave the shell behind.”
To me, an eggshell seems like cramped quarters for a baby chick about to hatch out. I am surprised that they take the time and have the ability to chip away a ring around the widest part and cut the egg in half. Amazing!
