Bearded vultures, booted eagles and a red-footed falcon are just some of the rare birds of prey that have been spotted in Belgium in recent days. Over the Netherlands, even the extremely rare imperial eagle has been sighted. Nature organisation Natuurpunt speaks of a "bird of prey tsunami". The reason why more rare birds are suddenly turning up here is clear: the warm weather.
When the air warms up, the earth heats up along with it. However, not all places on the earth's surface warm up at the same rate: for example, a dry clay soil warms up much faster than wet grassland. This irregular pattern of warming creates warm, upward air currents, better known as "thermal bubbles", in places where the earth warms up fastest.
Large birds of prey make grateful use of these thermal bubbles to gain altitude without using much energy and then glide on. This allows them to travel over long distances virtually without using any energy meaning on warm days they sometimes end up in Belgium.
On Thursday, a large group of griffon vultures was seen over the Heuvelland, in West Flanders. The closest breeding colonies are in southern France and Spain, according to Natuurpunt, it is very rare to see them here.
Last weekend, even griffon vultures were spotted in our country, but according to Natuurpunt, they will in all likelihood soon drift back south because they cannot find suitable breeding grounds or sufficient food in Belgium.
On Friday, a bearded vulture was spotted on the southern outskirts of Brussels. That bird comes from mountainous climes and is a rare sight even there, says Natuurpunt. "So, observing this giant over Brussels was definitely unique." The vulture was not marked or ringed, so the nature organisation suspects it is a wild bird.
Several booted eagles, black-winged kites, a common harrier eagle and a red-booted falcon were also seen scattered across Belgium, as were a lot of smaller birds from southern climes. In the Netherlands, a rare imperial eagle was even sighted.
Natuurpunt has a free data platform for bird watchers: www.waarnemingen.be . There you can see more pictures of griffon vultures in West Flanders and the bearded vulture over Brussels.