Population Dynamics of the Red Fox (Vulpes vulpes L., 1758) in Sweden

Abstract

The population dynamics of the red fox has been studied in two different habitats, the northern and the southern coniferous belts in Sweden. In the northern area the amount and quality of food varies greatly from year to year. Litter sizes, proportion of barren vixens, and mortality rates of cubs vary depending on the abundance of rodents. When rodents are rather few, young males more often than others disperse long distances. In the southern coniferous belt rodents also fluctuate in numbers but to a lesser extent. Alternative food is also more abundant, which results in a better and more stable food supply than in the north. The fox populations are also at higher densities here probably with smaller variations in number. Litter sizes vary a little but they are always large and the proportion of barren vixens is high. The mortality rate among cubs is also high with some variation between years. There is no correlation between the abundance of rodents and productivity or mortality rate. Population density per se is therefore assumed to be a factor of importance in regulating the number of foxes in the southern coniferous belt.