A postal questionnaire survey located over 700 feral cat colonies. Most were small well - established and lived in association with man, The feral cat population of Britain was estimated to be one million and is concentrated in urban areas. A domestic cat survey indicated a total population of 5.9 million cats in Britain. There appeared to be more females than males and a higher proportion of females than males were neutered. The effect of neutering on a colony of 30 adult cats. living in the grounds of Winwick Hospital, Cheshire, was examined. Individual cats were recognised by differences in coat colour and pattern, and data were collected by direct observation. The colony was studied for one year before and one year after neutering. Before neutering there appeared to be a seasonal fluctuation in numbers as a result of natality$ mortality and migration. Male immigrants were recorded. After neutering the colony remained stable in size and only one (female) immigrant was observed. The ecology and behaviour of 19 cats were studied in terms of home range, the distribution of, sightings in time, and sociability. Before neutering cluster analysis was used to identify groups of similar cats: males$ femalesp nomads and residents, After neutering no such groups could be distinguished and it is suggested that this was a result of changes in hormone balance. A mathematical model was developed for the study of associations within populations. It was shown that the cats tended to form more discrete social groups after neutering with fewer movements between groups. The adult cats were generally in good condition but there was evidence of exposure to feline calicivirus and feline herpesvirus. Trapping of cats appeared to be efficient and humane, and neutering was considered to be an acceptable form of population management.

A postal questionnaire survey located over 700 feral cat colonies. Most were small well - established and lived in association with man, The feral cat population of Britain was estimated to be one million and is concentrated in urban areas. A domestic cat survey indicated a total population of 5.9 million cats in Britain. There appeared to be more females than males and a higher proportion of females than males were neutered. The effect of neutering on a colony of 30 adult cats. living in the grounds of Winwick Hospital, Cheshire, was examined. Individual cats were recognised by differences in coat colour and pattern, and data were collected by direct observation. The colony was studied for one year before and one year after neutering. Before neutering there appeared to be a seasonal fluctuation in numbers as a result of natality$ mortality and migration. Male immigrants were recorded. After neutering the colony remained stable in size and only one (female) immigrant was observed. The ecology and behaviour of 19 cats were studied in terms of home range, the distribution of, sightings in time, and sociability. Before neutering cluster analysis was used to identify groups of similar cats: males$ femalesp nomads and residents, After neutering no such groups could be distinguished and it is suggested that this was a result of changes in hormone balance. A mathematical model was developed for the study of associations within populations. It was shown that the cats tended to form more discrete social groups after neutering with fewer movements between groups. The adult cats were generally in good condition but there was evidence of exposure to feline calicivirus and feline herpesvirus. Trapping of cats appeared to be efficient and humane, and neutering was considered to be an acceptable form of population management. / Royal Society for the Prevention of Cruelty to Animals. The Feral Cat Working Party.