The video of the ringing at Woluwe-Saint-Pierre

The two juvenile falcons of the City Hall of Woluwe-Saint-Pierre were ringed on the 13th of May

The operation of the ringing of the falcon chicks has been described in detail, step by step, in the blog of May the 8th (link: of the tagging event of the  young falcons in Uccle. The same procedure was followed here, as it is everywhere in Belgium. The principle is always the same: to collect the data useful for monitoring of the species in a minimum of time. We know from experience, shared around the world, that ringing is not at all harmful to falcons. But it is obvious that Peregrine parents do not appreciate the presence of visitors close to their young. So, the fastest the young are ringed, the better! You will find attached to this blog the ringing video in Woluwe-Saint-Pierre.

The brood of Woluwe-Saint-Pierre counts this year a male and a female. Perfect balance! But is that always the case? Yes ! Among the 11 falcons ringed at the communal house since the arrival of the Peregrine falcons in 2014, there are 6 females and 5 males. Is the sample too small to make strong statements? Right! Therefore, let’s consult the data available in the ringing files of the Royal Institute of Natural Sciences. It shows that 1994 falcons were ringed (not counting the ones of 2019 yet) since the return of the nesting Peregrine falcon in Belgium in 1994. Of these ringed falcons, the proportion of females is 48.7% and therefore that of males is 51.3%. One can therefore speak of "sex-ratio" at equilibrium. In other words, there are as many males as females in the population.

The female of Woluwe-Saint-Pierre laid this early March 4 eggs but the couple raises 2 falcons. What happened to the 2 unhatched eggs? One egg was found in the nest when the chicks were ringed. Its observation indicated that the egg was not fertilized or that its development was interrupted in the very first days of incubation. Indeed, it contained only liquid (not very nice ...).  But the other egg was not found, not even a trace. Obviously, he was evacuated by one of the parents. This corroborates the hypothesis that he died during the hatching process. Some images at the time of hatching showed a partially beak-cut egg, which ultimately did not hatch. Very remarkable images recorded at the Cathedral of Saints Michael and Gudula during two previous nesting cycles showed the female evacuating a "dead" egg at the same pre-hatching stage. Does the female realize that such an egg presents a risk of infection for her healthy falcons and that it is therefore necessary to evacuate it from the nest? While a dead egg or not fertilized but not cracked does not pose any concerns? The hypothesis is seductive and ... reasonable!

The female juvenile is marked with a black ring engraved with code B:3 while the code of the ring of her brother is G:6. In the next ten days, they will take off for the first time and discover the magnificent valley of Woluwe!


Photo 1: The male of Woluwe-Saint-Pierre is circling around the pinnacle during the banding operation (photo DV).

Photo 2: The female of Woluwe-Saint-Pierre, like all female Peregrines is daring! She comes to alarm closely as her falcons are ringed (photo DV).