Brooding and vocalizations in Woluwe-Saint-Pierre

For the ninth consecutive spring, a pair of Peregrine Falcons is nesting at the top of the tower of the Woluwe-Saint-Pierre town hall. It was, at the time of their arrival in 2014, the eighth couple identified in Brussels. They are now a dozen of Peregrine pairs in Brussels.

From the top of the 65 m high building, the falcons have an absolutely exceptional view of the east of Brussels. Placed on the balcony of the nest, or, even better, at the top of the spire which culminates above the steeple which houses the carillon, the Peregrines can observe the sky above the Woluwe park, the Woluwe valley and of its many ponds (a Natura 2000 area). On the horizon, so a few tens of seconds of flight for a hunting Peregrine, there is the thousand-year-old Forest of Soignes of nearly 5,000 ha, most of which is also classified as a Natura 2000 zone. The Peregrine pair from Woluwe-Saint-Pierre therefore lives in one of the “greenest” areas of Brussels.

The male nesting this year is the same since the first nesting in 2014. He hatched and was ringed in the spring of 2012 in the bell tower of the Saint Antoine church in Etterbeek, another of the 19 municipalities that make up the Brussels- Capital city. The female is unbanded. This has been the case since 2014 as well. It is therefore impossible to say whether it is the same or whether she has been replaced by another female, once or several times, in the meantime.

Among Peregrines, male and female share the task of incubating the eggs. In general, the female broods all night. The male broods relatively early in the morning. The female will then go to feed and probably also “stretch” her wings. Depending on the individual, depending on the circumstances, she will return to her eggs after an hour or, on the contrary, during the morning. She then broods all afternoon, until the male comes to take over again. His absence is then, in most cases, of short duration. She returns without delay to ensure brooding during the night.

Peregrines are often very talkative during these brooding relays. Video 1 shows the female finishing her night of brooding. It is 06:18; she calls the male. The latter answers; we hear it distinctly, without yet seeing it. She obviously heard him perfectly. She therefore knows that he has understood the message and she carefully gets off the 4 eggs and flies into the sky. There follows a series of cries between the two partners before the male comes to take care of the eggs. Same principle in video 2. But here, it is 08:48, so it is the female who comes to take over from the male. The two partners find themselves together in the nest and, again, communicate intensely! Talkative Peregrines!

In Woluwe-Saint-Pierre, the female laid her first egg this spring on March 21, more than 2 weeks later than the female from Uccle and 9 days later than the female from the cathedral. What is the reason for this discrepancy? Mystery. The weather conditions are obviously the same for all Peregrine pairs nesting in Brussels. This parameter cannot therefore be invoked. One possibility is that it is a new, inexperienced female. But as she is not ringed, just like the one that nested last spring, it is absolutely impossible to conclude. Still, the second egg was laid on March 24, the third on March 26 and the fourth and last on March 28. Incubation began, as usual, on the day of the laying of the third, which makes it possible to expect a hatching for April 27. However, in Uccle and the cathedral, the incubation period has been extended by 4-5 days. In question? Probably the cold weather that prevailed in Brussels in early April. It is therefore likely that the hatching of eggs from Woluwe-Saint-Pierre will also be delayed. Patience!

Video 1. Brooding relay between the female and the male in Woluwe-Saint-Pierre, listen carefully to the vocalizations of the male, who cannot be seen, but who signals his presence to the female.

Video 2. Here, it is the female who takes over from the male on the 4 eggs. The Peregrines are always very talkative in such circumstances!