The Peregrine Falcons of the ULB

The Peregrine pair currently nesting at the top of the belfry that adorns the historic building of the Université Libre de Bruxelles, on the Solbosch campus, was discovered in early spring 2019.

This is one of the last couples to arrive in Brussels. Something (very) surprising, the belfry in question is located barely 900 m from an office building which culminates at 102 m and where another pair of Peregrines have been nesting for almost 15 years. This is undoubtedly the closest distance between two Peregrine pairs living in Brussels. Peregrines are indeed extremely territorial. They can be so vindictive when an intruder is entering their living space that the confrontation can easily end in the death of one of the protagonists… But I’ll tell you more on this later!

Both partners of the pair are banded. This allows us to know that it is the fifth consecutive year that these two have nested together at the Solbosch campus. But it also makes it possible to know their place of birth – pardon of hatching – and their age. Indeed, most ringed Peregrines are ringed when they are still a falcon, and we can still “easily” reach the nest to ring them.

The female was born in the spring of 2014, in a nest box installed on a building that houses an automobile assembly line, not far from Sittard, along the Meuse, downstream from Maastricht. The distance between Sittard and Brussels is 106 km. In a straight line, of course, which does not necessarily correspond to the distance actually traveled by this female Peregrine before coming to settle in Brussels.

The male was hatched in April 2012 at the Notre-Dame de Laeken church, not far from the Royal Palace and its famous greenhouses. The distance between the church of Laeken and the belfry of the ULB is only 7700 m. A huge difference compared to the origin of his partner!

Since 2019, the pair have successfully nested each spring in the same nest at ULB. A total of 9 falcons took their first flight from the belfry: 2 in 2019, 3 in 2020, 2 in 2021 and 4 last year. How many will there be this spring? It is possible that the result will be exceptional because male and female have been taking turns to incubate for almost a month … 5 eggs. Normally, Peregrines lay 3 or 4 eggs. Rarely 2, exceptionally 5 or 1! This year, therefore, we are happy observers of two exceptional cases, but in different directions. The female of the cathedral laid 1 egg, that of the ULB laid 5. This is also what biological diversity is! To be complete, it should be added that the ULB female has already laid 5 eggs. It was in the spring of 2022. One of her eggs was broken under undetermined circumstances. Are we going to witness 5 chicks to hatch? Patience, hatching is expected in the next few days!

Blog 15042023 video 1. View from the top of the belfry of the Solbosch campus of the ULB: the female goes back to her nest, the male, who was incubating, gives way to her.

Blog 10042023 video 2. The ULB female joins her exceptional clutch of 5 eggs!