prey/ km2, but less in other parts of the year. When food is in surplus, the red fox caches the food in small holes, which are disguised with earth, twigs and leaves (Henry, 1996). The fox’s hearing is of paramount importance for distant and close-up detections of prey. It is very sensitive to lower sounds which correspond to the sounds that small mammals make underground under snow or in cover (Henry, 1996). The red fox shows the best performance of hearing at 3500 Hz but the range of correctly located sounds was 900-14000 Hz (Lloyd, 1980). Vision in foxes plays an important role in finding food in daylight but is subordinate to hearing and smell at twilight (Lloyd, 1980). Smell is important for scavenging and for communication with conspecifics. The red fox is usually described as a solitary carnivore, though recent literature now acknowledges that its social behaviour is complex (Voight, 1988). The red fox has never been observed to hunt in packs, as does the social living wolf. However, the red fox may live in female/male pairs or in a family group during the mating and breeding period, but each member has its own home range, dens and resting sites. A family group will consist of one male only and an additional number of females. When a family group contains several adult vixens, they are generally kin (MacDonald, 1980, Voight, 1988). Only a minority of adult vixens in a group will breed, and nonbreeding vixens are socially subordinate to breeding vixens (Hersteinsson and MacDonald, 1982). Those non breeding females might act as helpers (Voight, 1988; Von Schantz, 1981). Non-breeding females that become pregnant have been reported to abort or to desert their cubs (Von Schantz, 1981). Communal denning (two vixens) and nursing has been observed in large family groups (Hersteinsson and MacDonald, 1982; Macdonald, 1980, Voight, 1988). In superior habitats density has been reported to be 30 foxes /km2 and in the arctic tundra as low as 0.1 fox/km2 (Voight, 1988). Density is cyclic, following the density of prey and outbreaks of diseases. Prime habitat for the red fox is a varied country (Henry, 1996), and the more diverse the area is the more the foxes seem to thrive. Types of habitat range from undeveloped woodland to truly urban. The territorial structure is dynamic changing between seasons (Niewold, 1980). In general, the size of a territory depends on climatic conditions, quality and abundance of food, available dens or suitable landscape for digging dens, water supply, suitable sites to rest or seek refuge, and the fox density. Niewold (1980) found male territories to be between 63 and 1000 ha and female territories between 54 and 880 ha, but Voight (1988) describes the range of red fox territories to be between 500 and 3400 ha, and mentions that the smallest territories (10 ha and less) are found in urban areas. Mean territory size is 1.16 km2 as reviewed by Servin et al. (1991) and 4 km2 as reviewed by Gittleman (1983). Male territories never overlap each other, but a male territory overlaps one or more female territories (Niewold, 1980). During spring and summer, activity is centred around the den. Daily travelling distances by adults rarely exceed 10 km. Males travel a mean distance of 9.82 km per 24 h, equally distributed in the night and day, whereas females travel a mean distance of 5.93 km per 24 h with a greater distance travelled at night than in the daytime (Servin et al., 1991). Woollard and Harris (1990) found that red foxes rest 35% of the time, forage actively 55% and move actively around for 10% of the time when observed from 2200 GMT to dawn. Usually the fox has one or two large dens to give birth and raise cubs in. Additionally it has a number of smaller dens or sites, used for daytime refugee (Takezatu, 1979, Lloyd, 1980). Sometimes the fox digs the den itself, but old ones are used, as well as abandoned rabbit burrows and badger dens (Lloyd, 1980;
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