The Distribution and Activity of the Invasive Raccoon Dog in Lithuania as Found with Country-Wide Camera Trapping

The raccoon dog (Nyctereutes procyonoides Gray, 1834) is an invasive mammal widespread in northern, eastern, and central Europe, where it damages biodiversity and carries a wide range of pathogens. Surveys of this species in Lithuania ceased before 2000, so there is a lack of scientific information on its distribution and relative abundance. In 2019-2022, we carried out a nationwide recording of raccoon dogs using camera traps (101 sites, sampling effort of 15,563 trapping days). The species was found at 64 sites (63.4% of the sites surveyed), with an average relative shooting frequency of 4.30 photographs per 100 days. The frequency of raccoon dogs was higher at camera sites where lynx (Lynx lynx Linnaeus, 1758) or wolves (Canis lupus Linnaeus, 1758) were recorded compared to sites where predators were absent (7.95 vs. 3.21 photos/100 days, p < 0.05). The highest raccoon dog activity (69.5% of records) was observed at night and at temperatures between -3 and +5 & DEG;C. Below -15 & DEG;C, animals were not active, while above 25 & DEG;C, there was very little activity. Diurnal activity (36.1% of daytime records in April-June) increased during estrus, gestation, and rearing of pups. We conclude that wide-scale camera trapping is a suitable method for raccoon dog surveys.