Hatching at Woluwe-Saint-Pierre!

4:46:10 p.m.: the first 2022 Peregrine falcon chick is hatched at Woluwe-Saint-Pierre!

The hatching of the eggs was expected to happen around April 27, considering a “normal” incubation of 32 days, but as it was the case in Uccle and Brussels-City, the incubation period was extended by 4 days. This seems to confirm that the (very) low temperatures recorded in Brussels at the beginning of April, when incubation had started for only a few days, had an effect on the development of the chicks. Here is another example of the profound influence of the weather on the annual cycle of animals. If these meteorological “abnormalities” follow one another, we are in a context of phenological disturbances resulting from climate change.

Since morning, at least one chick has been cheeping while still in its eggshell. This is a normal phenomenon, it marks the beginning of communication between individuals. But it's always impressive and exciting to watch an egg yelling!

After hours of methodically work chiselling the shell on the side of the large end, the falcon chick manages to “pop” what is now an egg shell hood. Using its legs, it then pushes itself out of the other part of the shell. This last part of the hatching process is clearly visible in video 1. We even see a small wing stretching stealthily! The female raises herself up slightly for a few moments, probably to make it easier for her chick by giving him more space. Hence, the parents never intervene in the hatching process. They do not help their chicks. It must extract itself from the shell. On the other hand, at the very moment the chick has hatched, the mother falcon covers it and keeps it warm. It shouldn't get cold!

Still on video 1, we see another behaviour: the female eats the organic matter that remains in the egg shell! It's always like that ! We may think that it must be particularly nutritious substances! Listen closely, you can distinctly hear two kinds of cheeping, one sounding more dull than the other. A second falcon chick, still in the egg, begins to communicate with the outside world.

At 7:30 p.m., the male arrives for the first time at the nest since hatching occurred. He brings a blackbird to the female who raises herself up from the eggs and her chick, seizes the prey and flies away immediately. The male, perched on the edge of the balcony, discovers the spectacle. His first 2022 falcon chick is well and truly hatched. He looks to the left, to the right and takes over the incubation task. However, he does not feed the chick.

Twenty minutes later, the female returns. She enters directly into the nest, next to the male who immediately slips away. She doesn't feed the falcon either. It's not necessary ! In the last hours before hatching, it has absorbed the rest of the yolk (or “yellow egg mass”), a concentrate of energy, in its stomach. The phenomenon is most likely explained by the fact that in the event of bad weather and therefore the impossibility for the parents to feed their new-born young, the latter will be able to survive at least 24 hours without external food supply. And here again, we can discover the difference in behaviour between individuals. By comparison, at the cathedral, the couple tried to feed their falcon when it was only a few hours old. And it didn't work. Is it related to the inexperience of the cathedral couple? Or is it a difference in intellectual capacity?

Three eggs have yet to hatch in Woluwe-Saint-Pierre, this will probably be for tonight and tomorrow. Patience!

Video 1. Hatching of the first 2022 falcon chick from Woluwe-Saint-Pierre.

Video 2. The male discovers his first 2022 chick.

Video 3. The female returns to relay the male while incubating the chick and the 3 eggs still to hatch.

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