Raccoons, a non-native species originating in North America, are becoming a growing problem in Poland.
The animals raid nests and occupy nesting boxes. Birds accounted for around 25 percent of the raccoons' food, according to an analysis of their diet.
Around 14,000 raccoons were shot across the country last year, compared with 7,000 two years earlier, according to Weronika Baranowska, a PhD student at the University of Warsaw, who conducted the research together with biologist Dr. Magdalena Bartoszewicz.
Existing measures, such as spikes or small collars on nesting boxes, can deter native predators such as martens but do not stop raccoons.
According to the researchers, slippery barriers made of materials such as plexiglass and placed around tree trunks, at least 1 metre high, are the only effective protection for nesting sites.
Raccoon litters in the park averaged more than four young, compared with an average of three in comparable studies in Germany.
Baranowska said efforts to tackle the species should account for its breeding sites and that no single method, whether shooting raccoons or transferring them to sanctuaries, would solve the problem on its own.
She argued that locating entire litters and euthanising the young before they become independent could prevent them from dying slowly if their mother is killed.
Anyone who spots a raccoon in Poland should report it to authorities responsible for tackling invasive species.
(sp/gs)
Source: PAP