Spacing patterns in a rural cat population in Sweden

Liberg, O. (1980). Spacing patterns in a population of rural free roaming domestic cats. Oikos, 336-349.

Spacing patterns in a population of domestic and feral cats in a rural area in southern Sweden were investigated by visual observations, trapping and radio tracking. Females lived alone or in groups around human households. Within each female group the home ranges almost completely overlapped, but between different female groups there was little or no overlap. Most females remained in the same place all their lives, but a few individuals moved and became established at new households, invariably one where there were no other female cats. There were always six to eight feral, well established males in the area, with moderately overlapping home ranges. These ranges were considerably larger than those of females, and one male might include several female groups within his home range. Young males, born in the area, stayed with the female group, where they were born until they were 1.5-3 yr old. They then left and tried to settle somewhere else. Spacing patterns in this cat population can be explained by the influence of proximate and ultimate factors, among which intraspecific aggression and adaptation to living in human households are the most important. Parallel evolution of lion and house cat social organizations is discussed.

Identification of wolf-dog hybrids

Vilà, C., C. Walker, A.-K. Sundqvist, Ø. Flagstad, Z. Andersone, A. Casulli, I. Kojola, H. Valdmann, J. Halverson, & H. Ellegren. 2003. Combined use of maternal, paternal and bi-parental genetic markers for the identification of wolf–dog hybrids. Heredity 90 (1): 17-24.

The identification of hybrids is often a subject of primary concern for the development of conservation and management strategies, but can be difficult when the hybridizing species are closely related and do not possess diagnostic genetic markers. However, the combined use of mitochondrial DNA (mtDNA), autosomal and Y chromosome genetic markers may allow the identification of hybrids and of the direction of hybridization. We used these three types of markers to genetically characterize one possible wolf–dog hybrid in the endangered Scandinavian wolf population. We first characterized the variability of mtDNA and Y chromosome markers in Scandinavian wolves as well as in neighboring wolf populations and in dogs. While the mtDNA data suggested that the target sample could correspond to a wolf, its Y chromosome type had not been observed before in Scandinavian wolves. We compared the genotype of the target sample at 18 autosomal microsatellite markers with those expected in pure specimens and in hybrids using assignment tests. The combined results led to the conclusion that the animal was a hybrid between a Scandinavian female wolf and a male dog. This finding confirms that inter-specific hybridization between wolves and dogs can occur in natural wolf populations. A possible correlation between hybridization and wolf population density and disturbance deserves further research.

See more about wild canid hybridisation with dogs

Cat's diet and prey impact in Sweden

Liberg, O. 1984. Food habits and prey impact by feral and house-based domestic cats in a rural area in southern Sweden. Journal of Mammalogy, 65(3): 424-432

Natural prey of domestic cats in the Revinge area in southern Sweden during 1974-79 was related to prey abundance, annual production, and availability. Of 1437 scats collected, 996 contained remains of vertebrate prey. Most cats (80-85%) were house-based and obtained from 15 to 90% of their food from natural prey, depending on abundance and availability of the latter. Wild rabbits (Oryctolagus cuniculus) were the most important prey, and cats responded functionally to changes in abundance and availability of this prey. Prolonged snow cover made rabbits vulnerable to cats irrespective of abundance. Small rodents were the second most important cat prey, while brown hares (Lepus europeus) and birds were less important. In a period with high rabbit abundance, cat predation corresponded to 4% of annual production of rabbits and to about 20% of annual production of field voles (Microtus agrestis) and wood mice (Apodemus silvaticus). Prey choice of feral cats was similar to that of house-based cats, but as the former subsisted almost completely on natural prey, their absolute intake (294g/day during years with high rabbit abundance) was 4 times that of an average house-based cat (66 g/day).