With the RaptorCAM owls hatching, now seems a good time to take about egg teeth.

Many birds (and other creatures that are born from eggs) are born with an egg tooth to get through their shell. It is a hard, pointy protrusion at the top of their beak. It’s pretty much like if they had a tiny can opener built in.

They lose it or absorb it after about a week after they hatch.

From Wikipedia:

When it is close to hatching, a chick uses its egg tooth to pierce the air sac between the membrane and the eggshell. This sac provides a few hours’ worth of air, during which time the chick hatches. When a chick is ready to hatch from its egg, it begins the process of “pipping”; forcing the egg tooth through the shell repeatedly as the embryo rotates, eventually cutting away a section at the blunt end of the egg, leaving a hole through which the bird may emerge. Some species, including woodpeckers, have two egg teeth; one on both the upper and lower bill. After time the egg tooth falls off or is absorbed into thegrowing chick’s bill.

Some precocial species such as the kiwi, and superprecocial species including megapodes, do not require an egg tooth to assist them in hatching. They are strong enough at the time of hatching to use their legs and feet to crack open the egg. Megapode embryos develop and shed their egg tooth before hatching.

For reference, precocial, means they are born more developed than average, and can largely care for themselves from birth. Chickens and ducks are common precocial birds, while songbirds are not. Superprecocial birds are born with eyes open, having coordination, can run, and catch food. Megapodes (Australian mound building birds) hatch with fully developed flight feathers, and can many times fly on the day they’re born!