The ruddy duck, a small but aggressive species, has recently appeared in parts of Slovakia. (source: sdakotabirds.com)
Slovakia has confirmed new sightings of two invasive bird species: the ruddy duck and the Egyptian goose.
The ruddy duck is currently the fastest-spreading bird species in the country, and has lately been observed nesting near Partizánske, Trenčín Region, reports the news agency TASR. In the case of the Egyptian goose, there have been only isolated sightings, so there is less reason for concern.
The ruddy duck's rapid spread is causing alarm among conservationists, including Jozef Ridzoň from the Slovak Ornithological Society/BirdLife Slovakia.
Threat to people walking dogs
Ornithologists have recently observed the ruddy duck, which originated in North America but was imported into the UK in the 1940s, nesting in western Slovakia, including around Partizánske. The species is known for its aggressive behaviour in nesting grounds, by which it displaces other species and even poses a threat to people walking their dogs, said Ridzoň.
Problems with ruddy ducks have also been reported at Kuchajda Lake in Bratislava, leading to the regular need for state nature protection officials to capture ducks based on visitor complaints.
Similar aggressive behaviour has been noted in other locations, with native species struggling to adapt. Therefore, close monitoring is underway prior to the implementation of counter-measures.
Invasive mammal species are a bigger problem
Other non-native bird species, such as the mandarin duck and the black swan, have started nesting in Slovakia without displaying similarly invasive behaviour.
However, a more significant concern applies to invasive mammal species like the American mink and common raccoon dog, which have had a detrimental effect on local wildlife populations and also require control measures.
"The American mink destroyed the colony of dozens of nesting common terns in the protected bird area of the Dunajské Luhy several times," said Ridzoň.
