Exceptional nesting and images at the ULB!

We certainly can say that this is a special kind of spring for the Peregrine couple who has lived at the ULB since 2019!

The reversal of the situation has already been discussed in the blog of 05/04 (link to Season 2022: take care, your eyes! - Falcons for everyone 2022) of 06/04 (link to We were just talking… ! - Falcons for everyone 2022) and 20/04 (link to Turnaround at the ULB! - Falcons for everyone 2022).

We were therefore aware of the fact that after having deserted the bell tower of the historic building of the University, they tried to nest in a church steeple located a few hundred meters away, the couple returned to its “traditional” nest. On April 20, thunderclap, there are 3 eggs in the ULB nest (video 1)! We can therefore easily think that the suspected nesting at the Saint Adrien church has failed and that the couple is attempting a second egg laying. Similar behavior is well known in cases of premature nest failure. If the eggs are "lost" during the first days of incubation, female Peregrines are able to start a second clutch nearby. The characteristic of this second laying is to count fewer eggs than the first. Three eggs at the ULB, this observation therefore corroborates this hypothesis.

Well…no ! Video 2 dated 04/22 shows... 4 eggs. And video 3 dated 04/24 shows… 5 eggs! A laying of 5 eggs is exceptional for the Peregrine Falcon! And if it's a second clutch, it's incredible!

That being said, the ULB Peregrine female has already laid 5 eggs! It was last spring. One egg, however, was broken at the start of incubation while another did not hatch. Three falcons fledged thus at the end of May. We know that Peregrines, the important clutches, the exceptional clutches, are due to exceptional females and not to punctually or locally abundant food as is the case in many species of owls. We can therefore observe the nesting of an exceptional female at the ULB!

And what about the male? Its role is essential in brooding, feeding chicks, hunting. For Peregrines, the sharing of tasks between male and female is a reality. The investment of both partners is essential to the success of nesting. Of course, the male also has an essential role in … fertilizing the eggs. Video 1 captured a rare sequence: copulation at the entrance to the nest! Proof by image that the male, at the very least, indeed accomplished this crucial role!

So where are we today at ULB?

The same pair as since 2019 started a (second?) nesting around April 15.

The female laid 5 eggs.

Incubation started on April 21.

Hatching is expected around May 22.

In 18 years of monitoring Peregrine Falcons in Brussels, this will be the first time that such late nesting has been observed. To be continued, live!

Video 1. 20/04, mating at the entrance to the nest!

Video 2. 04/22, the female has just laid her fourth egg.

Video 3. 04/24, five eggs at ULB!

Video 4. 06/05, The female returns to her eggs

Video 5. 07/05. Male and female incubate the eggs.

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