Raptor Propagation: Getting out of the egg is hard work!

Once the egg’s air sac is in draw down, the chick’s lungs begin to function at an increased capacity. At this point, the chorioallantois membranes begin to reduce their blood flow. Once the membranes have shut down, the chick can safely break the membrane and begin pipping the shell.

It takes 24-72 hours for the chick to go from pip to hatch. During this time, the chick begins breaking up the area around the initial pip, sometimes creating a hole in the shell (see post from March 1, 2008 for a video of this part of the hatch). At this point, if the egg is held gently to your ear, the chick can be heard clicking and chirping inside the egg.

Next, the chick turns in its shell, using the egg tooth to break a line around the circumference of the large end of the egg. This part of the hatch progresses gradually, with the chick turning, then vocalizing, then stopping to rest before it resumes.

When the chick emerges from the egg, its down is damp and matted. Its closed eyes are large and bulging. The chick also has a prominent muscle along the back of its neck known as the “hatching muscle” which disappears 1-2 days after hatch.

During hatching, the egg yolk is retracted into the chick’s abdominal cavity, where it secretes through the “yolk stalk” into the small intestine and from there to the stomach for digesting. Thus, the yolk continues to nourish the chick through the first 24 hours of its life.

For further reading, I recommend James D. Weaver’s Falcon Propagation: A Manual on Captive Breeding which was the primary source for this post.

In the next installment of “Raptor Propagation”, I’ll discuss imprinting and hand raising chicks.