Uccle’s two falcons have hatched!

The hatching of the 2 eggs of the Uccle Peregrine pair was expected last Wednesday after 32 days of incubation. The first chirps were heard on Thursday. Hatching was therefore imminent but... we had to wait until Sunday morning to see the first chicks emerge from the shell on its own! The second falcon chick broke free from its shell this morning, shortly before dawn.

This is obviously not the first time we have observed this behaviour, but each time it is a real wonder!

First there is this communication between the egg and the outside world. As weird as it might be, the egg chirps loudly! Hence, the falcon chick, still in the egg, chirps loudly! This is the first stage of the delicate hatching process. This step creates a first contact between the chick and its parents. And we can indeed see that the behaviour of parents is changing. The female in particular incubates her eggs longer.

Next step: the chick rotates in the egg and pierces the membrane which leads to an air pocket located on the “big” end of the egg. This pocket can reach almost 20% of the volume of the egg. It is enormous! The falcon chick will then be able to ‘unfold’ a little and start to breathe. But above all, this new position, in this new volume, will allow it to conscientiously shear the shell by rotating and pecking. Therefore, the chick is equipped with a small “tool”: a small, very hard protrusion on upper mandible of its beak. Millimeter by millimeter, the chick, rotating and pecking, breaks the calcareous membrane that has protected it for 32 days or a little more. When he has completed the test, all he must do is push with all his strength using his feet which are still completely folded in order to “pop” the cap of the egg. The work is exhausting. Several times the chick pauses, obviously to rest. And then he takes up the task again because he can't stay imprisoned for too long.

When it comes out of the egg, the chick is all in a ball! We see this very clearly in the first video sequence. Quickly, but gently, he will unfold, lay on his stomach and... rest again. Their first coat of down is still all wet. Hence, it must dry out upon hatching quickly otherwise it will get cold.

And then it’s time for their first meal…

video 1. Shortly after hatching, the chick appears curled up in a ball, its down is all wet, it is protected, brooded by its mother.

Video 2. Four hours later, the male arrives at the nest. The female immediately leaves, and the first falcon chick of 2024 becomes visible. As she leaves, the female rolls off the hatched egg shell. We can see very well how the big end has been perfectly cut. The falcon's down is almost dry, but it still seems exhausted. His eyes are still closed.

Video 3. The female arrives with prey, but the falcon is probably still too exhausted to take a first meal. She will therefore hide the prey. She'll bring it out later.

Video 4. 7:40 a.m. this morning, the second falcon was born! It is still partially wet. Like the day before, the male comes to discover it. We can now see the two hatched shells.

Video 5 8:25 a.m. this morning, time for the first meal!