I won't take very long now. The little eyases are preparing to hatch. That will probably be the day after tomorrow when the first one will make it's escape. Because of the fact that the space inside the egg is getting very thight the chick has to take care to move it's head into the right position in time.
About 3 days before hatching it moves it's head under it's right wing with his beak towards the expanding aircell. The head should along the longside of the egg, only then the eyas will be able to cut and break the eggshell in half.
The last couple of days before hatching are of rest, of getting enough energy to make the escape. All the eggwhite has been consumed, there is however yolk left. This is being sucked up into the abdomen via the cloaca. This yolk contains enough nutrients to feed the eyas during the first 24-48 hours after hatching.
And then there is that important moment when the chorion-allantoide membranes can no longer supply the eyas with enough oxygen anymore. Suffocation leads to contraction of the hatchmuscle in the neck and this makes the eggtooth to pipp through the aircellmembrane. For the first time the chick breathes through it's lungs. And screams.......
The parents react immediately to this soft screaming from within the egg.
It will take another 24 hours before the oxygen depletes in the aircell and again suffocation makes the hatchmuscle to contract and the eyas pipps the eggshell.
It will keep on pipping and turning, pipping and turning untill it has broken the eggshell in two halves before it finally hatches. It is really something else. A very exhausting job for such a dear little fragile creature to get out!
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