Northernmost record of reproduction of the expanding golden jackal population

Golden jackal (Canis aureus) is expanding north in Europe. So far, its reproduction has rarely been reported in the expansion area. In this paper, we describe the first cases of reproduction of golden jackal from northern Poland, 500 km north from previously reported records. In summer 2015 and 2017, golden jackal juveniles (four and five individuals, respectively) sightings were recorded near Kwidzyn in Vistula river valley, where jackals have been observed repeatedly since 2015. These are the northernmost records of golden jackal reproduction in Europe. Since 2015, golden jackal was recorded in 15 locations in different parts of Poland, usually in the vicinity of larger rivers in mosaic habitats. The reproduction records suggest local establishment of population with predicted population increase and further expansion. First observation and record of reproduction in the same year suggest that expansion of golden jackal in Poland took place earlier and was not recorded, probably due to lack of knowledge on the species and failure to recognize its individuals.