The eggs of the Saint Job Church in Uccle are hatching!
The first cheeps were heard around 3:30 p.m. this Sunday, April 13 in Uccle. But not just ‘cheeps’, Peregrine Falcon cheeps! At 16:05, the female raises herself up slightly. She turns her 4 eggs. The cheeping is intense. Listen carefully while watching the first video in the appendix! We observe a crack in the eggshell! The crack is clearly visible, as always on the side of the large end of the egg. Hatching will be soon!
The female has laid 4 eggs between 5 and 11 March. Almost every time the eggs are laid 48 hours apart. The energy expenditure is indeed incredible for the bird. Each egg weighs on average 50 gram. The extremes range from 36 to 58 gram. This means that a female Peregrine who normally weighs 1 kilo will "produce" 20% of her weight in eggs within a few days!
The eggs are not incubated immediately. They stay uncovered until the penultimate or even the last egg is laid. So Peregrine falcons abandon their eggs without supervision?! Not really, because obviously, at least one parent is constantly survising, sitting on the weather vane or watching out from one of the towers of the Church of Saint Job. Beware the intruder approaching the nest. He will inevitably be vehemently attacked! Peregrines are very good parents.
Why the eggs are then not incubated as soon as the first egg is laid? Simply because in that case, there would be a delay of 6 to 8 days between the hatching of the elder and the younger chick. And that’s a problem, especially for the Peregrine parents. The food brought to a weeklong falcon is not the same as that to a newly hatched chick. A very small falcon must be covered and kept warm almost constantly while older chicks can be gradually left alone. The eldest may tend to dominate or even crush the smallest; Peregrine falcons are growing fast! Millennia and millennia of natural selection have therefore shaped this rhythm which allows a nesting cycle to offer the greatest chances of brood success and therefore of the perpetuation of the species!
19:50:58, the male brings a prey in the nest. He clearly understood that hatching will happen soon, because otherwise he does not bring food to the nest. But the female is "screwed" on her eggs. It is too early! The male leaves.
20:38:25, the female comes to relay the male who is now incubating the eggs. Male Peregrines take an important part in the nesting period. So he raises up to give her back the 4 eggs. Incredible luck, it's just the moment an egg is opening up and a chick hatches. We can see it very well. It is obviously all wet, it will still take several hours before its magnificent white down dries and completely covers it.
For the sixth consecutive spring falcons have been born in Uccle!
Video 1: First cheeps at Saint Job church in Uccle
Video 2: The male of Uccle brings a first prey, but it's still too early!
Video 3: Hatching live at Saint Job church in Uccle