Social Factors Affecting Reproduction Amongst Red Foxes

Abstract

In some habitats foxes live in social groups comprised of one adult male and several adult vixens. These groups occupy territories from which neighbouring groups are excluded. Elsewhere, foxes live in territorial pairs but recent research suggests that at least small groups are found in many habitats (Abies, 1975, Macdonald, 1980). On Boar’s Hill, Oxfordshire, a rural-suburban habitat where foxes live in stable groups of between 4–5 adults in territories of about 40 hectares, radio-tracking, direct observation, handling during trapping and occasional post-mortems all confirmed that many vixens did not rear cubs (Macdonald, 1979a). For instance, in 1974 one group consisted of three vixens, aged 9, 6, and probably 2 years, of which only the eldest reared cubs. Considering the four groups for which I have complete data in 1973–74, 6 out of 15 vixens (40%) reared cubs. Of these four groups a mean of 38.75% (S.D. ±15.5) of vixens in each group bred, that is only one or two vixens bred. More fragmentary information from the other groups on Boar’s Hill also suggested that many adult vixens did not rear cubs. There was no evidence of cub mortality, suggesting either that “barren vixens” did not conceive or that the embryos did not reach full term. Lumping data from 1973, 1974 and 1975, 12 of 24 vixens studied on Boar’s Hill reared young. In other study areas similar observations were made. A group of four vixens were observed at Ein Gedi (Israel) in 1976 and only one of these bred; within one group on Oxfordshire agricultural land one vixen did not breed in 1974, but did so in 1975 after the disappearance of another vixen who had bred the previous year.