This image from 11:09 am, Tuesday, April 22, 2008, clearly shows a pip site on one of the eggs. Scott Wright arrived on site at 11:30 and had first hand confirmation of the pip. By the time Museum staff arrived on scene at approx. 3:00 pm. the opening had been enlarged to the size of a dime. We expect the hatch to be completed tonight.
Pipping is the act of creating a breach in the shell and shell membrane so that the chick can establish respiratory function. After the pip there is a quiet phase where the chick draws blood back into its body from the shell membrane.
Once complete, the chick will then vigorously score the inside of the shell with its egg tooth while simultaneously pushing against the blunt cap of the egg with its neck. After scoring the shell for two thirds of its circumference the chick pushes against the cap and it flexes back enough for the chick to push its way out. It generally takes 24-36 hours between the onset of the pip and actual hatching. The parents do not assist in the hatching process. Since the hole was being rapidly enlarged during the day, the pip probably occurred Monday afternoon.
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