Red fox Vulpes vulpes density and habitat use in a rural area of Western Poland in the end of 1990s, compared with the turn of 1970s

The red fox Vulpes vulpes (Linnaeus, 1758) density and habitat use were studied in open farmland of western Poland, where forests covered only 6% of the area. During 1997-2000, nocturnal spotlight counts (in spring and early winter), the location of breeding sites and snow tracking were carried out, and the feeding habitat was described based on the stomach content of shot individuals. The average fox density estimated on the ground of spotlight counts was 1.02 individuals/km in spring and 1.63 ind./km in early winter, while the winter density obtained from the results of track counts was 1.26 ind./km2. The average breeding population density, calculated as the double density of breeding sites (mean 0.31/km ), amounted to 61% of the average total spring density, which indicates the occurrence of surplus individuals in the population. The searching intensity of farmland by foxes did not changed with the increasing distance from forests, but relatively larger number of individuals was observed <0.5 km than 0.5-1.0 km away from settlements. Out of 81 identified breeding sites, 17% were located in forests and 83% in farmland. The predominant ingredients of the fox's diet were farm livestock and small rodents (44.4 and 43.8% of the stomach content volume, respectively). The fox density in the study area was 5.4 times higher, compared with the turn of the 1970s, and changes in the habitat use consisted of more intensive occupation of open farmland and the use of human-produced food. Thus, these changes may have been among reasons of the increase in the fox density in western Poland.