Abstract
During the period 2012–2016, distribution of the common hamster, Cricetus cricetus, was monitored in Bohemia, Czech Republic. Between the harvest and subsequent field ploughing, i.e. in August and September, we visited all regions in which occurrence of the species after 1990 was reported in previous studies. There, in every square of the K. F. M. E. mapping grid we checked at least four harvested crop fields, i.e., cereals (preferably wheat and barley), sometimes also alfalfa and various vegetables, and examined also field balks and road ditches. In addition, during all parts of the year we recorded hamster road casualties. Also some personal reports by experienced co-workers were used. Altogether, we recorded hamster presence in 290 sites covering 75 K. F. M. E. squares. The area of the hamster occurrence in Bohemia consists of one big and one small sub-areas, most probably isolated from each other. They form a strip ca. 250 km long and mostly ca. 30–60 km wide. It runs from the lowlands along lower reaches of the Ohře river, through the Prague Plateau, lowlands along the Labe river up to the Svitavská pahorkatina Upland. The easternmost confirmed localities were near Svitavy. The altitude of most of the hamster localities varies between 130 and 300 m, in the Pražská plošina Plateau up to 400 m (altitudes of four exceptional localities near Svitavy are between 462 and 503 m). In some lowland regions of Bohemia the hamster is still common and locally abundant. The hamster prefers deeper soils, mostly various types of chernozem, luvisol and cambisol. It avoids moist places and extensive fields of maize and rape. All our hamster localities are situated in plots of the open agricultural landscape covering several tens of square kilometers. The hamster is also able to inhabit ruderal places in the periphery of villages and towns. During the second half of August and first half of September, the number of dead hamsters in roads increased considerably, suggesting that the traffic causes a not inconsiderable portion of hamster mortality.
About the Border between Two Phylogroups of the Common Hamster (Cricetus cricetus) (Cricetinae, Rodentia)
