Secondary poisoning of bearded vultures throught stray dog carcases' consumption in Pakistan

About seven rare bearded vultures, two Tibetan wolves and several foxes have perished after consuming the carcasses of stray dogs poisoned to death by the workers of municipal committee, Booni, and disposed of at the desert of Kaghlusht in upper Chitral...

Virus-vectored immunocontraception to control feral cats

Courchamp, F. & S.J. Cornell. 2000. Virus-vectored immunocontraception to control feral
cats on islands: a mathematical model. Journal of Applied Ecology, 37: 903-913.

1.  Feral cats Felis catus introduced onto oceanic islands pose a major ecological threat to endemic vertebrates, but their control is difficult. Immunocontraception has not been considered previously as a method for their control or eradication, and therefore we used a modelling approach to assess whether virus-vectored immunocontraception (VVIC) might be effective.

2.  We compared the relative efficiency of cat control/eradication using immunocontraception and three different disseminating techniques, i.e. baits, genetically modified viral vectors, or both. We accounted for several forms of dynamic compensation likely to arise in a population with artificially reduced fertility.

3.  We conclude that, under the assumptions of our model, immunocontraception can control or eradicate feral cats on oceanic islands. VVIC was found to be a more efficient dissemination technique than baits, but an integrated method involving viral-infected baits was the most likely to lead to eradication.

4.  We advocate field trials of this VVIC technique, when available, under island conditions where any risks to non-target fauna would be minimal.

Modelling biological control of cat populations

Courchamp, F. & G. Sugihara. 1999. Modelling biological control of alien predator populations to protect native island prey species from extinction. Ecological Applications, 9: 112-123.

Introduced feral cat (Felis catus) populations are an important threat to many island vertebrate populations and to bird species in particular. Elimination of feral cat populations is desirable in most of these ecosystems. Release of a parasite species in these mostly immune-naive populations is thought to be an efficient eradication measure. Such an approach is theoretically investigated here, using a mathematical model that describes the effects of introducing a virus into the cat population on population dynamics of both the cat and its prey. We studied the effects of two types of introduced feline viruses: Feline Immunodeficiency Virus and Feline Leukemia Virus, both of which are good candidates for eradicating a cat population. Results show that eradication is possible with Feline Leukemia Virus, if natural immunity is sufficiently low. Feline Immunodeficiency Virus cannot fully eradicate cat populations, but can be an effective agent for long-term control of cat populations on islands where total cat eradication is not possible (e.g., there is a high likelihood of continued introduction of cats) or not desirable (e.g., when rats are present). Culling, which by itself would require a very prolonged and logistically demanding effort to eliminate cat populations, may be more efficient when applied simultaneously with virus introduction.

Mammals invaders on islands

Courchamp, F., J.-L. Chapuis & M. Pascal. 2003. Mammal invaders on islands: Impact, control and control impact. Biological Reviews, 78 (3): 347-383.

The invasion of ecosystems by exotic species is currently viewed as one of the most important sources of biodiversity loss. The largest part of this loss occurs on islands, where indigenous species have often evolved in the absence of strong competition, herbivory, parasitism or predation. As a result, introduced species thrive in those optimal insular ecosystems affecting their plant food, competitors or animal prey. As islands are characterised by a high rate of endemism, the impacted populations often correspond to local subspecies or even unique species. One of the most important taxa concerning biological invasions on islands is mammals. A small number of mammal species is responsible for most of the damage to invaded insular ecosystems: rats, cats, goats, rabbits, pigs and a few others. The effect of alien invasive species may be simple or very complex, especially since a large array of invasive species, mammals and others, can be present simultaneously and interact among themselves as well as with the indigenous species. In most cases, introduced species generally have a strong impact and they often are responsible for the impoverishment of the local flora and fauna. The best response to these effects is almost always to control the alien population, either by regularly reducing their numbers, or better still, by eradicating the population as a whole from the island. Several types of methods are currently used: physical (trapping, shooting), chemical (poisoning) and biological (e.g. directed use of diseases). Each has its own set of advantages and disadvantages, depending on the mammal species targeted. The best strategy is almost always to combine several methods. Whatever the strategy used, its long-term success is critically dependent on solid support from several different areas, including financial support, staff commitment, and public support, to name only a few. In many cases, the elimination of the alien invasive species is followed by a rapid and often spectacular recovery of the impacted local populations. However, in other cases, the removal of the alien is not sufficient for the damaged ecosystem to revert to its former state, and complementary actions, such as species re-introduction, are required. A third situation may be widespread: the sudden removal of the alien species may generate a further disequilibrium, resulting in further or greater damage to the ecosystem. Given the numerous and complex population interactions among island species, it is difficult to predict the outcome of the removal of key species, such as a top predator. This justifies careful pre-control study and preparation prior to initiating the eradication of an alien species, in order to avoid an ecological catastrophe. In addition, long-term monitoring of the post-eradication ecosystem is crucial to assess success and prevent reinvasion.

FIV epidemiology in rural cats

Courchamp, F., N. Yoccoz, M. Artois & D. Pontier. 1998. At-risk individuals in Feline Immunodeficiency Virus epidemiology: evidence from a multivariate approach in a natural population of domestic cats (Felis catus). Epidemiology and Infection. 121: 227-236.

Prevalence of Feline Immunodeficiency Virus (FIV) infection was measured during 6 consecutive years in a natural rural population of domestic cats. Sex, age, weight, origin, group size and presence of antibodies to FIV were recorded for each sampled cat. Logistic regressions were used to estimate the influence of the recorded parameters on infection. FIV prevalence rates are as high as 19.6% in the total population, and do not statistically change between years, after controlling for changes in samples' age structure. FIV infection is characterized by risk factors linked to aggressive behaviour: old mature male adults having dispersed are more likely to be infected. A study of the cats group size and of the spatial distribution of infected individuals indicates the absence of infection clusters in males, and suggests the importance of roaming in the spreading of FIV. In conclusion, FIV infection spreads, with low contagiousness, mainly between particularly aggressive individuals, and the virus is endemic in this population.

Impact of two feline retroviruses on natural populations of domestic cat

Courchamp, F., D. Pontier, E. Fromont & M. Artois. 1995. Impact of two feline retroviruses on natural populations of domestic cat. Mammalia. 59 (4): 589-598.

We compared the pattern of spread and the impact of two retroviruses, feline immunodeficiency
virus (FIV), and feline leukemia (FeLV) within natural populations of domestic. A four years epidemiological study shows that FIV is present in three studied rural cat populations, whereas FeLV is absent in one out of the three, with no evolution in time for either virus. Factros influencing FIV transmission are directly linked to agressive behaviour , while factors influencing FeLV transmission are rather characteristic of amicable interactions. Results of a deterministic model show that both infections are maintained in the population at a stable equilibrium between susceptible and infected animals, slightly reduce the number of individuals at equilibrium, and have long transmission rates. Results of a long term dynamical study indicate that the probability of dying from tese viruses is low in natural conditions, and that, despite their presence, the size and structure of the population remains stable.
In conclusion, despite FIV and FeLV have different spread patterns (FIV infects and kills at-risk individuals, while FeLV infects more indiscriminately), the impact of both retroviruses on cat populations seems to be low. 

Infection strategies of retroviruses to control feral cats

Fromont, E., Courchamp, F., Pontier, D., & Artois, M. (1997). Infection strategies of retroviruses and social grouping of domestic cats. Canadian journal of zoology, 75(12), 1994-2002.

It is thought that parasites may exert selective pressure on the social structure of host populations. We compared the impact of feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), two retroviruses commonly found in domestic cats (Felis catus). Because of low transmissibility and virulence, both infections have a worldwide distribution and low prevalence. Transmission modes differ: FIV is transmitted only through biting, while FeLV transmission occurs by biting, licking, grooming, and sharing food and from mother to fetus. FeLV is also more pathogenic than FIV. We compared FIV and FeLV prevalence and risk factors within five populations of cats. FIV infection occurred almost exclusively among adult male cats fighting to acquire and maintain dominant status. Classes at risk for FeLV infection included sexually intact cats allowed to roam freely. The impact of FeLV on host population growth was greater than that of FIV but varied among populations. Our results show that FIV is favoured by individual aggressiveness and a hierarchical social system, while FeLV is more prevalent among socially active cats. FeLV may constitute a source of selective pressure against numerous amicable contacts, particularly in urban cat populations, where aggression among individuals is reduced.

Modelling FIV

Courchamp,F., D. Pontier & M. Artois. 1995. Modelling the Feline Immunodeficiency Virus within populations of domestic cats (Felis catus). Journal of Biological Systems, 3 (3): 769-777.

We attempt to model the circulation of the Feline Immunodeficiency Virus (FIV), a retrovirus analogous to the HIV, within populations of domestic cats. Domestic cats exhibit different patterns of population dynamics, social behaviour and reproductive strategies. In fact, cats can be either solitary or living in large social groups, with many intermediate states.

The aim of the presented model is to provide a conceptualization of the mechanisms of FIV spreading rather than to be a predictive tool. As one of our goals is to integrate easily new informations when available, and to remain simple and close to the biological reality, parameters, such as sex, age classes and dispersion, have been incorporated successively. This model can also be adapted to different types of cat populations by simple changes, as it could be to other host populations. A study of the stability of the model has been done. Based on available data, values of two parameters has been estimated: the carrying capacity and the transmission rate. Results are in good accordance with biological data.

Political perspective on TNR on a university campus

Dombrosky J, Wolverton S. (2014) TNR and conservation on a university campus: a political ecological perspective. PeerJ 2:e312

How to manage the impact of free-ranging cats on native wildlife is a polarizing issue. Conservation biologists largely support domestic cat euthanasia to mitigate impacts of free-ranging cat predation on small animal populations. Above all else, animal welfare activists support the humane treatment of free-ranging cats, objecting to euthanasia. Clearly, this issue of how to control free-ranging cat predation on small animals is value laden, and both positions must be considered and comprehended to promote effective conservation. Here, two gaps in the free-ranging cat—small-animal conservation literature are addressed. First, the importance of understanding the processes of domestication and evolution and how each relates to felid behavioral ecology is discussed. The leading hypothesis to explain domestication of wildcats (Felis silvestris) relates to their behavioral ecology as a solitary predator, which made them suited for pest control in early agricultural villages of the Old World. The relationship humans once had with cats, however, has changed because today domesticated cats are usually household pets. As a result, concerns of conservation biologists may relate to cats as predators, but cat welfare proponents come from the position of assuming responsibility for free-ranging household pets (and their feral offspring). Thus, the perceptions of pet owners and other members of the general public provide an important context that frames the relationship between free-ranging cats and small animal conservation. The second part of this paper assesses the effects of an information-based conservation approach on shifting student’s perception of a local Trap–Neuter–Return (TNR) program in introductory core science classes at the University of North Texas (UNT). UNT students are (knowingly or unknowingly) regularly in close proximity to a TNR program on campus that supports cat houses and feeding stations. A survey design implementing a tailored-information approach was used to communicate what TNR programs are, their goals, and the “conservationist” view of TNR programs. We gauged favorability of student responses to the goals of TNR programs prior to and after exposure to tailored information on conservation concerns related to free-ranging cats. Although these results are from a preliminary study, we suggest that an information-based approach may only be marginally effective at shifting perceptions about the conservation implications of free-ranging cats. Our position is that small animal conservation in Western societies occurs in the context of pet ownership, thus broader approaches that promote ecological understanding via environmental education are more likely to be successful than information-based approaches.

Gene flow between wolf and dog in the Caucasus

Kopaliani, N., Shakarashvili, M., Gurielidze, Z., Qurkhuli, T., & Tarkhnishvili, D. (2014). Gene Flow Between Wolf and Shepherd Dog Populations in Georgia (Caucasus). Journal of Heredity, esu014.

Shepherd dog; first-generation hybrid; wolf 

(all from Kazbegi, Georgia).

Photo courtesy: D. Tarkhnishvili & N. Kopaliani

We studied the distribution of the mitochondrial DNA haplotypes and microsatellite genotypes at 8 loci in 102 gray wolves, 57 livestock guarding dogs, and 9 mongrel dogs from Georgia (Caucasus). Most of the studied dogs had mitochondrial haplotypes clustered with presumably East Asian dog lineages, and most of the studied wolves had the haplotypes clustered with European wolves, but 20% of wolves and 37% of dogs shared the same mitochondrial haplotypes. Bayesian inference with STRUCTURE software suggested that more than 13% of the studied wolves had detectable dog ancestry and more than 10% of the dogs had detectable wolf ancestry. About 2–3% of the sampled wolves and dogs were identified, with a high probability, as first-generation hybrids. These results were supported by the relatedness analysis, which showed that 10% of wolves and 20% of dogs had closest relatives from an opposite group. The results of the study suggest that wolf–dog hybridization is a common event in the areas where large livestock guarding dogs are held in a traditional way, and that gene flow between dogs and gray wolves was an important force influencing gene pool of dogs for millennia since early domestication events. This process may have been terminated 1) in areas outside the natural range of gray wolves and 2) since very recent time, when humans started to more tightly control contacts of purebred dogs.

Herd and shepherd dogs in Georgia

See more about wild canid hybridisation with dogs

Relative effect of cats and other factors in removing rabbits from islands

Flux, J.E.C. 1993. Relative effect of cats, myxomatosis, traditional control, or competitors in removing rabbits from islands. New Zealand Journal of Zoology, 20: 13-18.

The outcome of control on 607 islands of known area round the world was analysed to identify the most effective way of removing rabbits. More islands have been cleared of rabbits by traditionalmethods of trapping, shooting, and poisoning than by introduced predators, competitors, or disease, but their relative efficiency could not be calculated because unsuccessful attempts have not normally been recorded. Where hares were introduced, rabbits subsequently became extinct on 27% of 105 islands; introduction of cats removed rabbits from 11% of 80 islands;myxomatosis from 10% of 119 islands; and cats and myxomatosis together from 3% of 40islands. All these control techniques were more effective on smaller islands than on large ones, but rabbits have “died out” naturally on 11% of the 607 islands, and this factor is not linearly related to island area.

Can we identify cat hybrids throught coat traits?

Ballesteros-Duperón, E., Virgós, E., Moleón, M., Barea-Azcón, J. M., & Gil-Sánchez, J. M.2014.  How accurate are coat traits for discriminating wild and hybrid forms of Felis silvestris?. Mammalia

Hybridisation between domestic cats, Felis catus, and wildcats, Felis silvestris, could lead to the genetic extinction of the latter; therefore, checking hybridisation rates in wild populations is of vital conservation importance. However, detecting hybridisation in the field is particularly challenging. Here, we aim to test the success of morphological-based procedures for discriminating wildcats from their hybrids and domestic cats, against genetic methods. We checked 17 putative Spanish wildcats by using two different classification systems based on coat patterns. None of the putative wildcats analysed in this study seemed to have an admixed genotype. Concordance between genetic and pelage approaches was almost total: only one coat classification produced mixed results with detection of one potential hybrid. Assignment was worse when performed in the field after a rapid examination of coat characters. We conclude that classification systems using coat traits could serve as surrogates of genetic approaches, but only after careful examination of those characters with more discriminatory power. Thus, the control of hybrid populations in the field as a management tool to preserve the genetic identity of wild forms is problematic if based on crude approaches or incomplete classification systems.

Distinctive traits of Wild cat (after Wildcat project)

See more on domestic cat introgression in wildcat

Impact of cats on Australian wildlife

Tidemann, C. R. (1994). Do cats impact on wildlife?. In Urban animal management: proceedings of the third national conference on urban animal management in Australia. Australian Veterinary Association, Sydney.

Cats can have beneficial impacts on wildlife by stabilising numbers of rabbits and exotic rodents. They can also have  adverse impacts, directly through predation and indirectly through the transmission of diseases. In many cases it is incorrect to single out cats as the sole factor responsible for declining wildlife populations, but the adverse impacts of cats may operate in concert with other factors, such as droughts, to finally push species into local or complete extinction. However, there is enough evidence available to indicate that a reduction in the numbers of free-ranging cats in urban areas would lead to a desirable increase in biodiversity in Australian cities. This statement, like any other to do with the management of complex ecosystems, needs to be viewed as a working hypothesis, requiring ongoing evaluation and subsequent modification as further information becomes available. Further information in this case could readily be collected by enlisting the aid of community groups to monitor the response of prey species to cat control programs. 

Urban cat ownership in Baltimore

Childs, J. E. (1990). Urban cats: their demography, population density, and owner characteristics in Baltimore, Maryland. Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals, 3(4), 234-244.

A door-to-door questionnaire survey of 430 households in two areas of Baltimore showed significant differences in cat ownership that were attributable to racial composition. Overall, 29.9% of white households owned a mean of 1.9 cats per cat-owning household, compared to 6.8% of black households owning a mean of 1.0 cat per cat-owning household. The mean age of cats was 3.9 yrs and 1.8 yrs in white and black households, respectively. In contrast, dog ownership in the two areas was nearly identical, with 25.6% of white and 29.1% of black households owning a mean of 1.5 and 1.3 dogs per dog-owning household, respectively. Overall, 62.8% of owned cats were spayed/neutered, 51.8% had received a vaccination in the last year, and 34.7% had been wormed during their lifetimes. A total of 31.6% of households allowed their cats to free-range; 42.5% of the 87 owned cats were in this category. The estimated densities of owned free-ranging cats were 7.0 and 2.8 cats per hectare, for the two areas. Driving counts of free-ranging animals in the two areas suggested a larger population of stray or feral cats in the location with lower reported cat ownership.

Humans and stray cats in NY

Haspel, C., & Calhoon, R. E. (1990). The interdependence of humans and free-ranging cats in Brooklyn, New York. Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals, 3(3), 155-161.

Based on the responses of 177 participants in a survey conducted in Brooklyn, New York, it was ascertained that 22.0% of the respondents fed free-ranging cats (2.8% daily and 19.2% occasionally). The food provided by feeders alone was estimated to support 1.71 to 2.10 cats per acre (4.2 to 5.2 cats per hectare), a density that is 1.35 times greater than the actual cat population. Other resources provided (e.g., shelter, medical help, adoption) were also estimated. Daily feeders were devoted to their cats. They continued to feed them despite the disapproval of their neighbors, financial constraints, or social obligations. Free-ranging cats appear to be in a mutually life-enhancing relationship with their feeders.

Home range of free-roaming cats in NY

Haspel, C. & R.E. Calhoon. 1989. Home ranges of free-ranging cats (Felis catus) in Brooklyn, New York. Canadian Journal of Zoology, 67: 178-81.

Home range size is stable among free-ranging cats in Brooklyn, New York. Marked male and female cats had mean home ranges of 2.6 (95% CI, 2.38–2.87) and 1.7 ha (95% CI, 1.57–1.98), respectively, as estimated by the population utilization distribution. Males had significantly larger home ranges, used the perimeter of their ranges more, and had greater variability in home range size than females. Gender differences in body weight accounted for observed differences in home range size; the seeking of estrous females by males could not account for differences in male and female home ranges. The availability of garbage or abandoned buildings, neighborhood, season, or experimental supplementary feeding did not influence home range size.

Feral house diet in Victoria

Coman, B. J., & Brunner, H. (1972). Food habits of the feral house cat in Victoria. The Journal of Wildlife Management, 36 (3): 848-853.

A total of 128 feral domestic cats (Felis catus) were collected from two different habitat types in Victoria. The stomachs of 80 of these cats contained food. Mammals, chiefly rabbits (Oryctolagus cuniculus), small murids, and phalangers, comprised some 88 percent, by volume, of the total dietary intake. Birds, cold-blooded vertebrates, and invertebrates were of secondary importance in the diet, accounting for only 5.2 percent, by volume, of the total intake. Grass and small twigs occurred frequently in the stomachs, but the volume represented was small (1.4 percent). Other items, mainly carrion and cat fur, accounted for 5.4 percent of the intake on a volume basis. Feral cats from undeveloped bush areas relied heavily on small indigenous mammals, whereas rabbits and house mice (Mus musculus) were the main mammalian prey species eaten in improved and semi-improved agricultural areas. Remains of indigenous mammals were not found in the stomachs of cats from the latter areas. It appears that feral cats are opportunist predators and scavengers and that the level of predation on any one prey type will depend largely on its relative availability. As a consequence, predation on native mammals is probably limited to those undeveloped areas of bush and scrub where such species are more plentiful.

Public perception of the problem of free roaming dogs and cats in Central Italy

Slater, M. R., Di Nardo, A., Pediconi, O., Villa, P. D., Candeloro, L., Alessandrini, B., & Del Papa, S. (2008). Free-roaming dogs and cats in central Italy: Public perceptions of the problem. Preventive veterinary medicine, 84(1), 27-47.

A cross-sectional telephone survey of randomly selected households examined the extent and types of problems associated with free-roaming dogs and cats in the Teramo province of Italy. The households were sampled randomly within each municipality; municipalities were combined into coastal, central hills and mountain regions for analysis. The survey was conducted in May and June of 2004 with a response rate of 74% (397/536). Ninety percent of respondents (N = 356) believed that free-roaming dogs and cats were a problem. They were most commonly concerned about personal safety, followed by animal welfare, public health and environmental sanitation. Sixty-nine percent of respondents (274) actually saw free-roaming dogs or cats where they live. While dogs were most commonly seen, cats were seen in greater numbers. Overall, 10% (39/297) and 5% (21/397) of respondents cared for free-roaming cats and dogs, respectively. Two-thirds of the respondents (251/397) believed that animals were abandoned because the owners lost interest. About 2/3 of respondents (251/397) reported that the community government should have the responsibility for dealing with free-roaming dogs and cats. The respondents supported the idea of building more shelters and controlling the birth rate as control measures rather than euthanizing dogs and cats. The results suggest that free-roaming dogs and cats are a very common sight in this part of Italy with substantial concerns by the residents. However, concerns about the animals’ welfare were clearly raised, supporting the laws that make it illegal to euthanize a healthy dog or cat in Italy. Using the information from this study, research on the underlying causes of abandonment of dogs and cats or failing to sterilize them should be undertaken to begin to address this problem. Further, national and regional funding must be provided to support existing laws which should help protect and eventually decrease the numbers of free-roaming and homeless dogs and cats.

Cats, mice and climate change impact on Marion island's birds

Huyser, O., Ryan, P. G., & Cooper, J. (2000). Changes in population size, habitat use and breeding biology of lesser sheathbills (Chionis minor) at Marion Island: impacts of cats, mice and climate change?. Biological Conservation, 92(3), 299-310.


Impacts on the native avifauna of sub-Antarctic islands by introduced vertebrates are well documented for species such as burrowing petrels (Procellariidae), but less is known about impacts on surface-nesting species. The sub-Antarctic Prince Edward Islands, comprising Marion and Prince Edward Islands, support an endemic form of lesser sheathbill (Chionis minor). Marked differences have developed over the last 20 years in winter habitat use and population trends of sheathbills between the two islands. Currently birds at Marion forage almost exclusively along the coastline and in penguin colonies during winter, but at Prince Edward they occur at higher densities and forage throughout the coastal plain. Compared to the 1970s, sheathbills at Marion are now less abundant around most of the island, forage proportionally less in the vegetation of the coastal plain, commence breeding with a lower body mass and lay smaller clutches. These changes are likely a result of a decrease in terrestrial macro-invertebrate prey, formerly an important winter food resource for sheathbills at Marion Island. The main biological difference between the two islands is the presence of many more introduced species at Marion, including house mice (Mus musculus) and feral cats (Felis catus) (now eradicated). We suggest that house mice are impacting the sheathbill population by consuming terrestrial macro-invertebrates, and that this impact has been exacerbated by the removal of feral cats, by the massive reduction in burrowing petrels (which promote invertebrate populations through manuring), and by climatic warming (which may be promoting higher densities of mice). This proposed web of interactions between sheathbills, introduced species, invertebrates and burrowing petrels needs to be further investigated, given the likelihood of further climatic change.

Feeding ecology and population dynamics of the feral cat in Australia

Molsher, R., Newsome, A., & Dickman, C. (1999). Feeding ecology and population dynamics of the feral cat (Felis catus) in relation to the availability of prey in central-eastern New South Wales. Wildlife Research, 26(5), 593-607.

The diet of feral cats (Felis catus) was studied at Lake Burrendong, central-eastern New South Wales, from July 1994 to June 1997. Mammals were the major prey in 499 scats that were analysed. Rabbits (Oryctolagus cuniculus) were the staple prey, while carrion was an important secondary food. Invertebrates, other mammalian prey, vegetation, birds and reptiles were generally minor components of the diet. Few significant seasonal differences in diet were found; however, invertebrates contributed less and possums more to the diet in winter and summer respectively. A significant dietary response was found to changes in rabbit abundance, but not for the other prey types. Cats continued to prey heavily on rabbits even after a 90% decline in rabbit abundance occurred, which coincided with the advent of Rabbit Calicivirus Disease (RCD). House mice (Mus domesticus) increased in importance in the diet ten months post-RCD. Although the abundance of cats was correlated with the abundance of some prey species, other factors may have influenced the observed patterns; these are discussed.

Home range of male feral cats in Central Australia

Edwards, G. P., De Preu, N., Shakeshaft, B. J., Crealy, I. V., & Paltridge, R. M. (2001). Home range and movements of male feral cats (Felis catus) in a semiarid woodland environment in central Australia. Austral Ecology, 26(1), 93-101.

There is a paucity of data on the movement patterns of feral cats in Australia. Such data can be used to refine control strategies and improve track-based methods of monitoring populations of feral cats. In this study the home ranges and movements of male feral cats were examined over 3.5 years in a semiarid woodland environment in central Australia. Two home range estimators were used in the examination: (i) minimum convex polygon (MCP); and (ii) fixed kernel. The most widely used method of estimating home range in feral cats is MCP, while the fixed kernel method can be used to identify core areas within a home range. On the basis of the MCP method, the long-term home ranges of feral cats in central Australia were much larger than those recorded elsewhere (mean, 2210.5 ha). Twenty-four hour home ranges were much smaller (mean, 249.7 ha) and feral cats periodically shifted their 24 h ranges within the bounds of their long-term home ranges. Core area analysis indicated marked heterogeneity of space use by male feral cats. Several instances where feral cats moved large distances (up to 34 km) were recorded. These long distance movements may have been caused by nutritional stress. Using data from the literature, it is shown that prey availability is a primary determinant of long-term home range size in feral cats. The relevance of the results to the design of management strategies for feral cats in central Australia is also discussed.

Diet of fox, dog and cat in south-eastern Victoria

Triggs, B., Brunner, H., & Cullen, J. M. (1984). The food of fox, dog and cat in Croajingalong National Park, south-eastern Victoria. Wildlife Research, 11(3), 491-499.

The diet of foxes, dogs and cats living in Croajingalong National Park in extreme south-easten Victoria was studied during 1979 and 1980. From 1397 scats collected over 20 months, remains of 22 indigenous and 7 introduced mammal species were identified. Remains of ringtail possums Pseudocheirus peregrinus predominated in the scats from all three predators (fox 58%, cat 56% and dog 38%). Other main prey species for the fox and cat were Antechinus spp.(24% and 15% respectively) and Rattus spp. (15% and 19%) and for the dog two species of wallabies, Macropus rufogriseus and Wallabia bicolor (34%), wombat Vombatus ursinus (11%), Antechinus spp.(l5%) and Rattus spp.(10%). Nonmammalian items for the three predators were birds, reptiles, fish, insects, crustaceans, molluscs and plant material.

Comparison between feral cat and fox diets in Australia

Catling, P. C. (1988). Similarities and contrasts in the diets of foxes, Vulpes vulpes, and cats, Felis catus, relative to fluctuating prey populations and drought. Wildlife Research, 15(3), 307-317.

The diets of the fox, Vulpes vulpes, and feral cat, Felis catus, were studied at Yathong Nature Reserve in semi-arid western New South Wales. The overall occurrence of rabbit was 45.1% in stomachs of foxes and 54.0% in cats, representing 51.3 and 82.6% respectively of the weight of stomach contents. Both predators exhibited a functional response to rabbits, Oryctolagus cuniculus, (their staple prey) during the rabbit breeding season. Predation on rabbits was greatest on an increasing prey population during good pasture conditions and a decreasing population during drought. After the rabbit breeding season, diet changed to other prey and resulted in an annual prey cycle which was similar for foxes and cats. Both predators successfully co-exist in the semi-arid environment by primarily utilising different age groups of the same staple prey and to some extent different supplementary prey. Foxes mainly ate adult rabbits and cats young rabbits. During the drought foxes preyed heavily on adult rabbits; cats ate some rabbits but relied heavily on other food sources. The supplementary prey of foxes were invertebrates, birds, reptiles and carrion; small mammals and fruits opportunely eaten. Invertebrates, birds, reptiles and small mammals were supplementary prey for cats with carrion opportunely eaten.

Home range and population ecology of feral cats in Australia

Jones, E., & Coman, B. J. (1982). Ecology of the Feral Cat, Felis catus (L.), in Souht-Eastern Australia III.* Home Ranges and Population Ecology in Semiarid North-West Victoria. Wildlife Research, 9(3), 409-420.

This paper reports home range sizes and population ecology of feral cats in a 19000-ha study area situated in the Victorian Mallee. Movements of six cats were monitored by radio-tracking for 8-21 months. Adults maintained discrete home ranges; areas varied from 3.3 to 9.9 (mean 6.2) km² for males and from 0.7 to 2.7 (mean 1 ,7) km² for females. Rabbit warrens, hollow logs and dense thickets were favoured daytime refuges. Mean daily straight-line distances moved bet-veen daytime refuges varied from 0.06 km for a female with juveniles to 1.67 km for an adult male. Relative abundance of cats over four years showed seasonal fluctuations, with summer maxima and winter or spring minima; the calculated mean summer and winter densities were 2.4 and 0.74 cats per km² respectively. Summer maxima were composed of adults, adolescents and juveniles; winter minima were usually composed only of adults. Mortality, presumably caused by a nutritional stress acting particularly on subadults, maintained the adult population at a relatively stable level.

Spacing patterns in a urban cat population in Italy

Natoli, E. (1985). Spacing pattern in a colony of urban stray cats (Felis catus L.) in the historic centre of Rome. Applied Animal Behaviour Science,14(3), 289-304.

Factors controlling the spatial organization of a colony of stray cats (Felis catus Linnaeus, 1758) in an urban environment were investigated. Neighbouring colonies of stray cats were also observed, but in less detail. The findings were that:

(1) the animals of the colony selected for intensive study showed an active spacing pattern, i.e. they were not randomly distributed within the boundaries of the study area;

(2) the existence of an active spacing pattern was related to the resources offered by the environment where the animals lived;

(3) these resources (food and shelter) were concentrated in some parts of the study area. Consequently, the animals used these parts more intensively than others. The observations carried out on neighbouring colonies of cats confirmed the results reported for the colony examined in detail.

Some workers consider domestic cats to be a unique resource for evolutionary studies of social behaviour because it has been shown that this species has a high degree of intra-specific variation of behaviour in contrasting habitats. The object of this study was to examine the spacing behaviour and the evolution of the domestic cat social system as a response to a particular urban environment.

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.

Myths and facts about “managed” cat colonies

Winter, L. (undated). Myths and facts about “managed” cat colonies. ABC

1. Cat colonies don't just die out in one or two years: Although promoters of Trap/Neuter/Release (TNR) often claim that the colonies die out through attrition in just a few years, there is very little evidence to support this claim. Even the Adams Morgan cat colony of only 30 original cats in the District of Columbia, which was "managed" by the founders of Alley Cat Allies, took 10 years to die out. It is often difficult to trap all of the cats, the cat food that is left out attracts more cats, and cat colonies often become dumping grounds for unwanted pets (Donald, R.L. 1992. Should Feral Cats Be Euthanized? Shelter Sense: 3-7). Volunteers can become overwhelmed and may not have all of the financial resources or the manpower needed to trap and alter every cat in a colony (Passamsi, w.c., D.W. Macdonald. 1990. The Fate of Controlled Feral Cat Colonies. Universities Federation for Animal Welfare, Hertfordshire, England. 48).
Please note the following: "It's just so overwhelming. I'm in over my head. I can't even afford to eat or buy clothes or do anything. I wake up in the morning hoping I can make it through the day." (Puzzanghera, J. 1995. So Many Cats, So Little Time, San Jose Mercury News, July 19, 1995.)

2. TNR is not meant to eliminate colonies of cats: The purpose of TNR is NOT to eliminate cat colonies, but to perpetuate them because cat feeders believe that if a neutered colony is removed, an intact colony will move in and take it's place.
Please see the following: "You will never get rid of the cats in that area, and it is not advisable to do that. Because if you're doing a neutering to eradicate the cats by neutering, and remove them completely from the area, you are just being the same as somebody who wishes to go and trap them out and kin them. All you're doing is delaying the day Of death." (From a presentation by Roger Tabor, Alley Cat Allies Seminar, "Focus on Ferals," July 8, 1994, Washington, DC.)
More cats may move into an area ONLY if the food source remains. If cats are trapped out and the food source is removed, a cat colony will not reform in that location. This is exactly what occurred at Riverside National Park where over 25 cats were being fed daily. Over the strong objections of the cat feeders and Alley Cat Allies, and in the face of a negative media campaign, the National Park Service removed the cats, the feeding was stopped, and no additional cats have congregated in the area. The Cats were not euthanized, but taken to a local Shelter (Sealy, D. 1996. Removal of a Colony of Free-Ranging Cats From an Area Administered by the National Park Service: A Case History, in: Proceedings of the 1995 International Wildlife Rehabilitation Council Conference, Virginia Beach, VA. Pp 75-77).

3. Cat colonies attract other predators: The cat food left out attracts raccoon, skunk, opossum, fox, coyote, and rats, all predators of birds and carriers of diseases that can be transmitted to other cats, wildlife, or humans, such as rabies. No one is neutering and giving rabies vaccinations to these animals to control their populations and the spread of disease. I have personally witnessed a huge rat hole right under a cat feeding station, and studies have shown that cats do not do a very good job of Controlling rat populations (Childs, J. E. 1991. And the Cat Shall Lie Down With the Rat, Natural History: 16 - 19).
I also have slides of raccoons at cat feeding stations, and e-mail messages from cat feeders discussing the problem of raccoon and opposum at their stations.

4. The cats are not always tested or vaccinated for fatal feline diseases: Some groups, such as the Feral Cat Coalition (http://www.feralcat.com/tpolicy.html), do not follow the American Veterinary Medical Association's guidelines which state that cats in a "managed" cat colony should be tested and vaccinated for infectious diseases and adopted or euthanized if positive. Thus, diseased cats in "managed" cat colonies could come in contact with and infect free-roaming pet cats. Cats with fatal feline diseases will suffer and die a miserable death, calling into question the very humaneness of this practice.

5. Domestic cats are not strictly territorial: Cat feeders will often say that altered cats defend their territory, and do not let other cats join the colony. There is scant scientific evidence to support this claim either. It is well-known that the home ranges of domestic cats overlap. In fact, Dr. Carol Haspel, who conducted a number of studies of cat colonies in Brooklyn, NY, says that cats occupying a certain area "absolutely do not" keep others out, "particularly if there is a feeder." (Donald, R.L. 1992. Should Feral Cats Be Euthanized? Shelter Sense: 3-7).

6. Well-fed, altered cats still kill birds and can impact wildlife populations: It has been extensively documented that domestic cats can severely impact seabird populations on islands (Moors, P.J. and I.A.E. Atkinson. 1984. Predation on seabirds by introduced animals, and factors affecting its severity. ICBP Technical Publication 2:667-690), and well-fed Cats still kill wildlife (Adamec, R.E. 1976. The interaction of hunger and preying in the domestic cat (Felis catus): an adaptive hierarchy? Behavioral Biology 18: 263-272.)
Cats and other predators can also have an impact on songbird populations in fragmented and isolated habitat (Wilcove, D.S. 1985. Nest predation in forest tracts and the decline of migratory songbirds. Ecology 66: 1211- 1214.)

Please see the following quote regarding a scientific study conducted in two California parks-one with over 20 cats that were fed daily, and one without cats:
Cats at artificially high densities, sustained by supplemental feeding, reduced the abundance of native rodent and bird populations, changed the rodent species composition, and may have facilitated the expansion of the house mouse into new areas. Thus we recommend that the feeding of cats in parks Should be Strictly prohibited. (Hawkins, C.C., W.E. Grant, М.Т. Longnecker. 1999. Effect of Subsidized House Cats on California Birds and Rodents. 1999 Transactions of the Western Section of The Wildlife Society 35: 29-33.)

Feral dogs as potential threat for pinnipeds

García-Aguilar, M.C. & J.P. Gallo-Reynoso 2012. Feral dogs at Isla de Cedros, Baja California, Mexico: a possible threat for pinnipeds. . Revista Mexicana de Biodiversidad, 83 (3): 785-789.

The presence of feral dogs (Canis lupus familiaris) in Isla de Cedros, Baja California, Mexico, has been documented for over 15 years. In the summer of 2009 and the winter of 2009/2010, 2 sampling surveys were conducted in the northeast coastal portion of the island to assess the diet of feral dogs in the vicinity of hauled out California sea lions (Zalophus californianus) and northern elephant seals (Mirounga angustirostris). Mammals were the most important prey group in the diet of dogs (85.4%). Our results show that in the northeast coast of Isla de Cedros, feral dogs feed on pinnipeds: the elephant seal was the most important prey in both seasons (43.3% in summer and 51.9% in winter), followed by the sea lion as the second most important prey during the summer (23.3%), while its importance decreased in the winter (5.8%). Besides the potential predatory activity, there is an important likelihood that pinnipeds could be infected by pathogens of dogs, with serious epizootic consequences.


García-Aguilar, M.C. & J.P. Gallo-Reynoso 2012. Perros ferales en la isla de Cedros, Baja California, México: una posible amenaza para los pinnípedos. Revista Mexicana de Biodiversidad, 83 (3): 785-789.

La presencia de perros ferales (Canis lupus familiaris) en la isla de Cedros, Baja California, México, fue documentada hace más de 15 años. En el verano de 2009 e invierno 2009/2010, se realizaron 2 campañas de muestreo en la costa noreste de la isla para evaluar los hábitos alimentarios de los perros en las cercanías de las zonas de reproducción y descanso del lobo marino de California (Zalophus californianus) y del elefante marino del norte (Mirounga angustirostris). Los mamíferos constituyeron el grupo consumido más importante en la alimentación de los perros (85.4%). Los resultados de este estudio muestran que en la costa noreste de la isla de Cedros los perros se alimentan de pinnípedos: el elefante marino fue la especie que más se consumió, con el mayor porcentaje en ambas temporadas (43.3% en verano y 51.9% en invierno); el lobo marino, fue la segunda durante el verano (23.3%), aunque su porcentaje disminuyó en el invierno (5.8%). Además del potencial impacto que el consumo por los perros pueda tener sobre las poblaciones de los pinnípedos, una amenaza adicional es la posible transmisión de los patógenos caninos, con serias consecuencias epizoóticas.

Eradication of cats and other aliens as conservation tool in isla Cabritos, Dominican Republic

Ortiz, R., Rijo, C., Ramnanan, N., Brocca, J., Jolley, W., Hall, T., Herrera-Giraldo, J.L., Swinnerton, K. 2014. The eradication of invasive species as conservation tool for protection and increase of populations critically threatened species in isla Cabritos, Dominican Republic.  VIII Congreso Biodiversidad Caribeña, Universidad Autónoma de Santo Domingo

The eradication of invasive alien species is one of the most valuable tools for effective conservation and protection of native wildlife on islands. The presentation disclosed efforts in 2012 and 2013 to eradicate feral cats (Felis catus) and donkeys (Equus asinus) on Cabritos Island, Lake Enriquillo, Dominican Republic. There, the invaders have negatively impacted many species, including one of the four subpopulations globally fragmented Ricord's iguana (Cyclura ricordi), endemic to Hispaniola and Critically Endangered. Local partners working with eradication experts assembled and trained a local field team to eradicate invasive species on this island, development and application of methods and strategies for removal. After six weeks, the team continued to work independently, with technical support and remote assistance. The cats were removed by cage-trapping and elevated leg-holder traps, the donkeys with the use of snares, most of them delivered to local community organizations. The primary objective of the project is the restoration of Cabritos, to ensure the survival of endangered species, maintain ecotourism initiatives and develop local capacity and support from the local government for future restoration projects islands. These activities take place in the framework of the project "Mitigating the Threats of Invasive Alien Species in the Insular Caribbean" implemented in the Dominican Republic by the Ministry of Environment and Natural Resources, with funding from GEF / UNEP.


La erradicación de especies invasoras como herramienta de conservación para proteger e incrementar poblaciones de especies críticamente amenazadas en las isla Cabritos, República Dominicana.

La erradicación de especies exóticas invasoras es una de las herramientas más valiosas y eficaces deconservación para proteger la vida silvestre nativa en islas.Se presentarán los esfuerzos realizados en 2012 y 2013 para erradicar gatos (Felis catus) y burros (Equus asinus) asilvestrados en la isla Cabritos, Lago Enriquillo, República Dominicana. Allí, las invasoras han impactado negativamente numerosas especies, incluyendo una de las cuatro subpoblaciones globalmente fragmentadas de la iguana de Ricord (Cyclura ricordi), endémica de la Hispaniola y en Peligro Crítico. Los socios locales, trabajando con expertos en erradicación, ensamblaron y entrenaron un equipo de campo local para erradicar las especies invasoras en esta isla, desarrollo y aplicación de métodos y estrategias de remoción. Después de seis semanas, el equipo local continuó trabajando de forma independiente, con apoyo técnico y asistencia remota. Los gatos fueron removidos por captura con trampas-jaula y trampas sujeta-patas elevadas; los burros con el uso de lazos, la mayoría de éstos entregados a organizaciones comunitarias locales. El objetivo primario del proyecto es la restauración de la Isla Cabritos, para garantizar la supervivencia de especies amenazadas, mantener las iniciativas de ecoturismo y desarrollar la capacidad local y el apoyo del gobierno para futuros proyectos locales de restauración de islas. Estas actividades se desarrollan en el marco del proyecto “Mitigando las Amenazas de las Especies Exóticas Invasoras en el Caribe Insular”, implementado en la República Dominicana por el Ministerio de Medio Ambiente y Recursos Naturales, con el financiamiento de GEF/UNEP.

Removing invasive mammals from Alto Velo Island, Dominican Republic

Herrera-Giraldo, J. L. , León, Y., Rijo, C. & Swinnerton, K. 2014. Restoring Alto Velo Island, Dominican Republic: Protecting important colonies of marine birds and habitats for endemic reptiles by removing exotic invasive spscies. VIII Congreso Biodiversidad Caribeña, Universidad Autónoma de Santo Domingo

Caribbean islands host numerous endemic species, unique ecosystems, and globally irreplaceable biodiversity. In the Caribbean Biodiversity Hotspot, invasive species have been identified as the greatest threat to biodiversity. Globally, about 80% of species extinctions have occurred on islands, with invasive species implicated as a primary cause. Worldwide, invasive species eradication is increasingly being used as a valuable conservation tool with which to successfully restore island biodiversity. In the Dominican Republic, a partnership between Grupo Jaragua, the Ministry of Environment and Natural Resources, and Island Conservation, has provided an opportunity to restore Isla Alto Velo through invasive species eradication. Alto Velo is part of the Jaragua National Park which is itself an Important Bird Area and a Key Biodiversity Area. The island is home to one of the largest breeding colony of sooty terns in the insular Caribbean and supports three species of reptiles unique to the island. A feasibility study indicated that the complete and permanent removal of invasive rats, cats, and goats from Isla Alto Velo is technically achievable. During the next months, the project partners will develop a systematic and science-based strategy to remove these invasive species from the island. The overall project goal is to create a wildlife sanctuary in the Dominican Republic where endemic and native species are free from invasive species impacts. In addition, this conservation action would promote the recovery of historically important seabird colonies and could provide future breeding habitat for the endangered black-capped petrel (Pterodroma hasitata), a species threatened by invasive vertebrates.




Restauración de la Isla Alto Velo, República dominicana: Protegiendo importantes colonias de aves marinas y hábitat para reptiles endémicos mediante la remoción de Especies exóticas invasoras

Las Islas del Caribe son refugio de numerosas especies endémicas, ecosistemas únicos y de una irremplazable biodiversidad a nivel mundial. Dentro de los Focos de Biodiversidad en el Caribe, las especies invasoras han sido identificadas como la mayor amenaza para la biodiversidad. Globalmente, cerca del 80% de las extinciones de especies han ocurrido en islas, siendo las especies invasoras uno de los principales causantes. Actualmente, la erradicación de especies invasoras se está utilizando cada vez más como un útil y eficaz instrumento de conservación para restaurar exitosamente la flora y fauna en islas. En la República Dominicana, una alianza entre el Grupo Jaragua, el Ministerio del Medio Ambiente y Recursos Naturales y Island Conservation, ha creado una oportunidad de restaurar la Isla Alto Velo mediante la erradicación de especies invasoras. Alto Velo es parte del Parque Nacional Jaragua, el cual es un Área Importante para las Aves y un Área Clave para la Biodiversidad. La isla provee refugio para una de las mayores colonias de la gaviota oscura en el Caribe Insular y para tres reptiles endémicos. Un estudio de viabilidad indicó que la remoción completa y permanente de ratas, gatos y chivos asilvestrados de Isla Alto Velo es técnicamente viable. Durante los próximos meses, los aliados del proyecto desarrollarán una estrategia sistemática y fundamentada en ciencia para eliminar estas especies invasoras de la isla. El objetivo general del proyecto es crear un santuario de vida silvestre en la República Dominicana, donde las especies endémicas y nativas estén libres de los impactos de especies invasoras. Además, esta acción de conservación promoverá la recuperación de las colonias de aves marinas y podría proporcionar hábitat para la reproducción del diablotín, una especie en amenaza por la presencia de vertebrados invasores.

Genetics of a dockyard cat population

Dards, J. L., & Robinson, R. (1983). Gene frequencies in a population of feral cats in Portsmouth naval Dockyard. Theoretical and Applied Genetics, 64(3), 197-204.

The free-living or feral cats of Portsmouth Dockyard were examined for the frequency of six mutant colour and coat genes. With the exception of one mutant, they were found to differ from the values to be expected for Southern England cat populations. The differences observed may have resulted from selection in the isolated environment (to produce a unique gene profile in terms of frequencies) or from a founder effect. If the latter, the observed frequencies could represent a relict population reflecting the frequencies of the town of Portsmouth before the dockyard was totally enclosed by a high wall. Some evidence of selection related to coat colour was found.

The behaviour of dockyard cats

Dards, J. L. (1983). The behaviour of dockyard cats: Interactions of adult males.Applied Animal Ethology, 10(1), 133-153.

A study was conducted on the feral cats living in Portsmouth Naval dockyard, an enclosed site with an area of less than 100 ha, supporting a population of about 200 adult cats. Data were collected by direct observation, and individuals were recognized primarily by coat pattern. The behaviour of mature tom-cats was observed with respect to females and to other mature males. Most toms visited several groups of females, but the frequency with which a particular group was visited varied between toms. Some toms spent most of their time with one group, adopting a role similar to that of a “pride lion”. The courtship and mating behaviour observed in the dockyard conformed with that recorded for laboratory cats. However, females in oestrus were not heard to call, but toms which were apparently seeking oestrus females emitted a characteristic cry. Up to 6 toms were observed in attendance on unreceptive oestrus females. Sexual behaviour was observed in most months, with peaks in the spring and autumn. Most of the aggressive interactions observed between toms and females were initiated by unreceptive females during courtship. Male aggression towards females was rare. Amicable behaviour was shown, and was more frequently initiated by females than by toms. Females appeared to interact amicably more frequently with toms with which they were familiar. No amicable behaviour between mature toms was observed. Interactions were characterised by aggression, tolerance or avoidance. Agonistic encounters were mainly ritualised, and few fights were observed. It is possible that a dominance hierarchy existed between toms, formed by fights when young toms first became sexually mature.