Nesting of Short-toed Eagles in the Visegrád Hills in 2015-2018

The Visegrád Hills lie in the picturesque Danube Bend along the right side of the river. This is the only place in Hungary where the Danube River is bordered by mountains from both sides. Nowadays, only one Short-toed Eagle pair nests in the area and represents the greatest ornithological value here. In the past century, the species had probably bred continuously in a low number (1-3 pairs) in the region proved by the data found in the literature. The first confirmed breeding attempt dates back to 1930. By 2015, the number of nesting pairs had shrunk to one pair. Due to thorough surveys carried out lately we can exclude the possibility of the presence of other pairs. There are several factors behind this reduction such as the widespread use of clear-cutting by the forestry and the alteration or disappearance of traditional foraging habitats, however, not knowing the nests’ exact locations in the past 20 years made them impossible to protect.
In 2015, 22 years later since the last known nest, we could record the species’ breeding by finding the active nest. This constitutes the very first confirmed and documented Short-toed Eagle nesting in the Visegrád Hills in the 21st century. On July 21, 2015, we marked the chick with a coded colour ring. In 2016, the pair occupied the same nest where we ringed the chick on July 8, which successfully fledged in August. In 2017, the pair chose a new site for building a nest, a lime dominated scree forest (Mercuriali-Tilietum). The nest was found 800 metres from the old one at the junction of two lime trees leaning on each other. The nest was covered with dense foliage being quite unusual for the species. This was the first known case of a nest being built on this tree species in Hungary. A male chick fledged from the nest which was ringed on July 6. In 2018, the pair renovated the same nest where we ringed the chick on July 21. We observed intruding individuals in all four years in the territory, sometimes close to the actively used nest.
On August 9, 2018, a colour-ringed subadult (4-5 calendar-year) Short-toed Eagle appeared in the vicinity of the nest. First, it was spotted 50 metres from the nest perching on top of a dead tree while it was observed again 700 metres from the here again perching in a clear-cut area. A few hours later, the bird was photographed flying about 4.5 kilometres far from the nest. Although, we obtained several photos and a video footage of this particular bird perching, its ring could not be coded due to the strong heat haze. This observation constitutes the first occasion of a Hungarian (blue ring on the right leg with white inscriptions starting with “A”) colour-ringed bird turning up in an active territory in Hungary!