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.

A survey of gastro-intestinal parasites was conducted on faecal samples collected from 379 feral cats and 851 native fauna from 16 locations throughout Western Australia. The prevalence of each parasite species detected varied depending upon the sampling location. Common helminth parasites detected in feral cats included Ancylostoma spp. (29.8%), Oncicola pomatostomi (25.6%), Spirometra erinaceieuropaei (14%), Taenia taeniaeformis (4.7%), Physaloptera praeputialis (3.7%) and Toxocara cati (2.6%). The most common protozoan parasites detected in feral cats were Isospora rivolta (16.9%) and I. felis (4.5%). The native mammals were predominately infected with unidentified nematodes of the order Strongylida (59.1%), with members of the orders Rhabditida, Spirurida and Oxyurida also common. Oxyuroid nematodes were most common in the rodents (47.9%) and western grey kangaroos (27.8%). Several species of Eimeria were detected in the marsupials whilst unidentified species of Entamoeba and coccidia were common in most of the native fauna. Primers anchored in the first and second internal transcribed spacers (ITS1 and ITS2) of the ribosomal DNA (rDNA) were used to develop a polymerase chain reaction-linked restriction fragment length polymorphism (PCR-RFLP) technique to differentiate the species of Ancylostoma detected in feral cats. Amplification of the ITS+ region (ITS1, ITS2 and 5.8S gene) followed by digestion with the endonuclease RsaI produced characteristic patterns for A. tubaeforme, A. ceylanicum and A. caninum, which were detected in 26.6%, 4.7% and 0% of feral cats respectively. Giardia was detected in a cat, dingo, quenda and two native rodents. Sequence analysis at the small subunit rDNA gene (SSU-rDNA) identified the cat and dingo as harbouring G.duodenalis infections belonging to the genetic assemblages A and D respectively. Subsequent analysis of the SSU-rDNA and elongation factor 1 alpha (ef1á) identified a novel species of Giardia occurring in the quenda. Attempts to genetically characterise the Giardia in the two native rodents were unsuccessful. Serological detection of Toxoplasma gondii was compared to a one tube hemi-nested PCR protocol to evaluate its sensitivity. PCR was comparable to serology in detecting T. gondii infections, although PCR was a much more definitive and robust technique than serology for large numbers of samples. Amplification of T. gondii DNA detected infections in 4.9% of feral cats and 6.5% of native mammals. The distribution of T. gondii does not appear to be restricted by environmental factors, which implies that vertical transmission is important for the persistence of T. gondii infections in Western Australia. These results demonstrate that cats carry a wide range of parasitic organisms, many of which may influence the survival and reproduction of native mammals. As such, the large-scale conservation and reintroduction of native fauna in Western Australia must not disregard the potential influence parasites can have on these populations.

Le chat haret est l’un des prédateurs invasifs les plus dommageables pour la biodiversité insulaire. Sa présence est associée à une perte de biodiversité sur l’ensemble des îles sur lesquelles il est établi, et où il constitue une menace pour de nombreuses espèces de vertébrés souvent endémiques et menacés. En Nouvelle-Calédonie des populations de chats harets sont présentes dans tous les milieux et habitats et l’étude de son écologie et de ses impacts sur la faune ont fait l’objet de ce travail de thèse. L’analyse du régime alimentaire sur 14 sites d’études représentatifs des 4 habitats majeurs a révélé un régime très diversifié et une forte prédation sur les vertébrés natifs et notamment sur le groupe des scinques, des roussettes et des pétrels. Parmi les 44 espèces de vertébrés retrouvées dans le régime alimentaire de ce prédateur invasif, la plupart sont endémiques et 20 listées comme menacées sur la liste rouge mondiale de l’UICN. Le suivi des déplacements d’individus équipés de colliers GPS au niveau d’une presqu’île abritant une importante colonie d’oiseaux marins, a permis de mettre en évidence de grands domaines vitaux pour les mâles, des domaines vitaux petits pour les femelles et des patrons de déplacements liés aux différentes étapes du cycle reproducteur des oiseaux marins. Ces éléments, couplés aux analyses de régime alimentaire suggèrent une prédation à une large échelle géographique, à la fois sur les adultes reproducteurs mais également sur les jeunes oiseaux proches de l’envol. Une opération expérimentale de contrôle d’une population de chats harets a été conduite sur cette presqu’île et a montré une faible durabilité des effets de la suppression des individus sur les densités observées et une rapide recolonisation du site. Les résultats de ce travail plaident pour la mise en place de mesures de limitation des impacts occasionnés et permettent en particulier de cibler les habitats de maquis et forêt humide comme prioritaires en matière de limitation des abondances. / Feral cat (Felis catus) is one of the most successful and harmful invasive predator species for island biodiversity. The presence of this alien predator species generally lead to dramatic loss of native island biodiversity and represents a serious threat for numerous endemic and threatened species. Feral cats have invaded the whole New-Caledonian archipelago and all its habitats. In this study, we focused on the ecology and impacts of this invasive predator on the outstanding endemic fauna found in the different habitats of the exceptional New-Caledonia biodiversity hotspot. Feral cat diet analyses on 14 selected sites representing the 4 main natural habitats revealed a high diversified diet and high predation rates on native species particularly on squamates, flying foxes and petrels. Among the 44 vertebrates species found into the feral cat diet, 20 are IUCN red-listed threatened species. Cat movements of eleven feral cats fitted with GPS collars have been studied in a western coast Peninsula hosting an important seabird colony. Male cats showed large home ranges while female showed small home ranges. Feral cats exhibited important movements within the studied peninsula linked with the breeding cycles of seabirds. GPS data coupled with dietary informations suggested a predation that concerned both breeding adults and fledgings bird, and at a large geographic scale as some feral cats have their core home range distant to the colony (>3km). We evaluated the effects of a high level but intense cat control on this site that showed a low sustainability of feral cat culling and a rapid recolonization process. Our results are pleading for the future limitation of feral cat impacts and call to focus first abundance limitation measures on maquis mosaic and humid forest habitats This study also provided information on the spatial extent and intensity of future control measures in the special context of a large and highly invaded island.