Moving ending of the nesting period in Uccle

In Uccle, the end of nesting was eventful. During the observation session on Sunday May 22, none of the (many) observers and photographers present managed to spot the 4 juvenile falcons at the same time. Same with the camera.

Nothing worrying a priori, since when they are close to fledge, the juveniles run from left to right and no longer remain continuously tight against each other. On the other hand, the camera connected to film the young at the entrance to the nest is not adjustable. It is therefore not possible to scan the entire nest in order to see what is happening there with precision.

And then there is amazement. Wednesday, May 25, 7 a.m., a juvenile falcon finishes a pigeon breakfast at the entrance to the nest. Its mother is perched on a clock hand. The juvenile falcon is exercising its wings, fledging is near (video 1).

A few minutes later, the mother returns. She enters the nest. She seems nervous, runs helter-skelter and then returns to the entrance of the nest. But she is almost out of sight of the camera. Only her left wing can be seen.

11:38 a.m., the mother falcon reappears in the field of the camera. We first see her from behind, then she appears completely and … she drags the remains of a juvenile falcon to the other side of the entrance of the nest (video 2)! The fourth juvenile is therefore dead. The observation of the black ring engraved with the CRD code indicates that it is the young female (photo 1). The mother will almost completely eat the remains and then take it out of the nest, as she does with “normal” prey.

So what happened? The young do not yet have enough strength to kill one of their own. And above all, they have no reason to do so since they have enough to eat. Even small, the falcons show no aggression towards each other. In eagles, predation of the eldest against the younger is regularly observed.

It also seems impossible that the falcon was killed by one of its parents. We would have observed a "fight" on camera. Do not forget that at this age, a juvenile female falcon already weighs 1 kg, therefore a weight equivalent to that of an adult female, therefore of its mother.

Could the falcon have been killed by a predator like a marten? No, it's impossible. First, because access via the interior of the tower is impossible. Then because the predator would have killed all the young. He would have had no "reason" to kill one and spare the other 3. One can be absolutely convinced that the juvenile falcon has not been killed.

2 hypotheses remain. Either the falcon has choked on prey. It already happened at the cathedral 15 years ago. Either the falcon was poisoned after feeding on intoxicated prey. It has already happened with parents at the Helmet church in Schaerbeek. However, it will not be possible to have confirmation of one or the other hypothesis because the mother has removed the corpse.

The death of a falcon is of course a sadness. But the important thing is that, on the whole, the population is dynamic and that many falcons fledge each spring in Brussels and in many other regions of Belgium. The population is close to 220 breeding pairs this year!

The three falcons fledged a few days later.

In the meantime the falcon from the cathedral fledged well but out of camera view as the transmission broke down again, sorry for that..

Video 1: A juvenile falcon finishes eating a pigeon

Video 2:  Mother Peregrine drags the remains of a falcon to the entrance of the nest!

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