Exceptional visit to the cathedral

Peregrine Falcons are (very) territorial birds during the breeding season. Why are these birds of prey ready to fight - at the risk of injury or even killing each other - to defend an air space and 3 gargoyles? We can propose two reasons.

First, nesting sites for a peregrine falcon are rare. It must be, at least in our region,on a cliff or, by substitution, at the top of a high building that gives the falcon direct access to the sky. In other words, the peregrine should only have to throw himself into the void in order to, with a minimum of effort, find himself carried by the air currents. But on this cliff or this building, the peregrine must also find a nest site. Peregrines do not build a nest themselves, otherwise it would be easy! In stead, they lay their eggs on the ground, in a crevice of the cliff, or behind a balcony, on a platform of a building, a corner where, for example, dried droppings of pigeons have accumulated. Of course, this site must be relatively dry and above all drained, otherwise the eggs or falcons would quickly be drowned. And this is not the case everywhere! Finally, the site must be free from disturbance - at some height. Peregrines, by virtue of their position as super-predators, can not stand being disturbed. they will therefore only settle on sites that offer them complete tranquility. But tranquility high above the ground, because what happens on the ground does not matter to them. At the Saint Job’s church in Uccle, the pair of falcons nest on the steeple, about twenty meters high. that's not very high for a peregrine. But here he has a holy and happy peace. And yet, the Place Saint Job, is mostly swarming with people: weekly market, shops, and even the annual fair. The Peregrine has no business with any of this, his domain is heaven! So the first reason, and probably the main one, that explains the territorial behavior of the peregrines is the defence of a nesting site which is, in fact, a rare commodity!

The other reason is more classic: the defense of a pantry. By excluding others of its species from a certain airspace, a couple of peregrines can ensure themselves oaf a certain availability in prey.

Observing territorial behavior of a peregrine is not common, but can happen about once a week when the observations take place very frequently, if not continuous, as it is the case for observation installed on the forecourt of the Cathedral of Saint Michel and Saint Gudula in Brussels. Filming the territorial behavior of a peregrine is therefore a rarity, let alone capturin a close-up! And yet this is what happened on April 13 at the cathedral (video 1 and video 2 26042018). But that's not all ! The intruder, who boldly landed on a gargoyle, is a hybrid peregrine bred in captivity. It is recognized by its plumage and the breeding ring that she wears on his right leg. It is probably a female hybrid between a peregrine falcon and a gyrfalcon. The fight will last from 10:39 to 11:50. The female of the cathedral will not stop attacking this  unfamiliar falcon. And then finally, she manages to destabilize the intruder. The intruder falls from the gargoyle and disappears in flight (video 3 26042018).

But why did this falcon born in captivity stay on the gargoyle for so long, instead of quickly moving camp when confronted with the intimidations of the breeding couple? Just because she was hungry! It is deduced by observing that she goes to the base of the gargoyle, to look for a remainder of prey, and to devour it in spite of the danger (video 4 26042018). What a story!

By the way, do not miss out and have a look at the camera 2 of the cathedral!