Visit to the Eagle Owls

The peregrine falcon is an apex predator. This means that it is at the very top of the food chain. Does he himself really have no predators? Not quite ! Indeed, he shares in Belgium and beyond in Europe, this position with the Eurasian eagle-owl. The largest nocturnal bird of prey in the world!

The eagle owls inhabit almost all of Eurasia. Like the peregrine, its range is therefore very vast. And, as with the peregrine, the female is larger than the male. In our latitudes, its wingspan can reach 180 cm for a weight of 2.5 kg. The values are respectively about 150 cm and 1.8 kg for the male. Still like peregrines, the eagle owls preferentially nest on cliffs. And, again like the peregrine, the eagle-owls have disappeared from Belgium and Western Europe through the fault of men. Just like peregrines (definitely!), they came back to us thanks to these same men who took matters into their own hands by implementing legislation beyond state borders: the famous European directive on the conservation of wild birds (1979) which prohibits and condemns the destruction, trapping, poisoning of eagle owls, peregrines and hundreds of other species.

The eagle owl returned to nest in Belgium in the early 1980s. A first family was discovered in the Amblève valley in 1982 and today, the population is estimated at between 220 and 240 breeding pairs, including 20-30 in Flanders! Like the Peregrine, the return of the eagle owl is Belgium is... super impressive!

So there are many similarities between these two birds. And a unique feature: if, during a nocturnal survey, an eagle owl comes across a peregrine, sleeping on a cliff... He will put it on his menu like a common pigeon! Eagle owls are therefore the only predators of adult peregrines.

Eagle owls and peregrines have therefore been closely followed in Belgium since the end of the 1980s for the former and the mid-1990s for the latter. The teams and collaborators of the Royal Institute of Natural Sciences list and observe nests in order to follow the evolution of the population of one compared to that of the other, in order to know the rate of success - or failure - broods, in order to observe the number of chicks per family. All these parameters, and a few more, provide a “dashboard” that simultaneously informs us of the dynamics of the two species. The goal: to sound the alarm in case of danger based on reliable data recorded over the long term. An example ? The data we have will allow us to evaluate objectively and reliably what are the consequences of the avian flu epidemic that we are currently experiencing.

And so, each spring, in addition to the families of peregrines, dozens of families of eagle owls are followed in Belgium. When possible, as for the peregrines, the little eagle-owls are banded. The photos in the appendix illustrate an operation carried out today. Just like peregrines, the number of chicks is between 1 and 4. It is a family of quadruplets that was observed today. And on the menu, there was no peregrine, but… a barn owl!

Blog 20052023 photo 1. A family of quadruplets of Eurasian eagle owls in the south of the Province of Namur

Blog 20052023 photo 2. Surprise!

Blog 20052023 photo 3. The weighing of the youngest (790 g)

Blog 20052023 photo 4. The weighing of the eldest (1561 g)

Blog 20052023 photo 5. A barn owl on the menu of the eagle owl family.

Blog 20052023 photo 6. Wild orchids (Orchis mascula) bloom near the nest

Blog 20052023 photo 7. The view of the eagle owls from their nest. Beautiful Wallonia!

Blog 20052023 video 1. Incredible mimicry! But orange eyes, the color of which will intensify further until the moment of flight