With no egg tooth to help the process, the kiwi chick has the exhausting job of kicking and pecking its way out.
The first sign that the chick is ready is when the egg jiggles slightly. It may stay still for 20 minutes, then jiggle again.
Eventually the chick will make a tiny hole in the air-filled sac inside the end of the egg, poke the pink tip of its beak through, and breathe air for the first time. Following this exertion, it may sleep for anything from 12-48 hours.
When it awakes, the chick tries again, kicking and pushing against the shell wall, which flexes as the baby bird struggles inside, mewing loudly. Eventually a crack or hole appears, and the chick’s beak pokes through the shell. As the shell slowly cracks open, the chick continues to struggle off and on, until at last it is free. The hatching process can take up to three days.
The parent stamps on the empty shell and buries it in the nest, or eats it to regain some lost calcium.
If a second egg has been laid in the clutch, this hatches faster than the first egg. The first chick can be anywhere between one and three weeks old when the second chick arrives.
Massive yolk to nourish chick
Kiwi chicks hatch with a large external yolk sac, which is gradually absorbed through their navel, over their first 10 days of life. This means they do not have to go outside to feed for the first few days. Although born with huge feet, chicks often can’t stand up because their bellies are so distended by the yolk sac.
Unlike chicks of other birds, the newly hatched kiwi is not covered in down. Instead, its feathers are covered in a slimy coat that dries and flakes off within 24 hours, leaving the chick a miniature version of its parents.