Ecology and genetics of wild-living cats in the north-east of Scotland and the implications for the conservation of the wildcat.
Wildcats (Felis silvestris) are considered to be threatened by interbreeding with domestic cats (F. catus). As a result of interbreeding, the definition of a wildcat in Scotland, UK, is contentious. Many authors consider pelage characteristics to be diagnostic, yet few data exist on sympatric cats with different pelages. A study of 31 wild-living cats was conducted between March 1995 and April 1997 in an area associated with wildcats. Seventy-four percent of cats caught had striped tabby pelages while 26% had other (non-tabby) phenotypes. On the basis of data from eight nuclear DNA microsatellite loci, there was no strong evidence of two groups, and tabby and non-tabby cats did not depart significantly from Hardy-Weinberg equilibrium. There were significant differences in gene frequencies and genotypes between the two pelage types. Non-tabby cats were also significantly more similar to domestic cats than tabby cats, although still noticeably differentiated from them. There were potential parent-offspring and sibling-sibling relationships between and within tabby and non-tabby cats, suggesting recent interbreeding. On average, however, non-tabby cats were genetically less related to each other than tabby cats. Radio-tracking revealed that non-tabby adult females had significantly larger home ranges than tabby adult females. However, for all other aspects of home range size, social organization, activity patterns and habitat use there were no significant differences between cats of different pelage type. The implications of these results are that traditional approaches for attempting to distinguish wild animals in the face of interbreeding with their domestic forms are neither accurate nor effective. Instead, conservation should focus on mechanisms for dealing with groups of animals below the species level. Specifically for wildcats in Scotland, conservation should focus on protection by area. If domestic cat controls are conducted within specified areas then the potential threat posed by interbreeding could be reduced.