Impact of a 3-year pet management program on pet population and owner’s perception

Costa, E. D., Martins, C. M., Cunha, G. R., Catapan, D. C., Ferreira, F., Oliveira, S. T., ... & Biondo, A. W. (2017). Impact of a 3-year pet management program on pet population and owner’s perception. Preventive Veterinary Medicine.

Although pet population management programs have been established worldwide, few reports on program evaluation have been carried out to date. Accordingly, a 3-year longitudinal study has been carried out in a 4,000 household neighborhood located within the metropolitan area of Curitiba, the eighth most populated city of Brazil. Visits were conducted and questionnaires completed to estimate and characterize the local pet population (animal sex, reproductive and vaccination status, street access). Care provided by owners, community perception on stray dog management and the possible changes were compared in these variables over time (2010 and 2013) were evaluated, after the establishment of a city pet population management program. In addition, associations between having children, owning dogs and cats, responsible pet ownership education and owner’s perception on stray dogs were statistically tested. A total of 354/4,000 (8.9%) household families were interviewed in 2010 and 70/354 (19.8%) of the same families again in 2013. No significant changes were found in overall number of dogs and cats and average pet age, animal care and owner’s perception on stray dogs following the 3-year population management program. In 2010, an average of 1.6 dogs and 0.3 cats were found per family, with slightly more females (51.3% dogs and 51.1% cats), adults (4.0 ± 3.5 years for dogs and 2.1 ± 2.4 for cats), intact (not neutered; 94.2% dogs and 84.0% cats) and lacking regular visit to veterinarian (71.6%). Although more families (53.1%) had children under 12 years old, no association was found between having children and having dogs and cats. Questionnaires revealed that owners perceived neutering/spaying to be the best pet population control method (42.4%), with “society” (50%) and “government” (49.4%) as responsible for pet population management. A significant positive association has been found between education level and the best way to control stray dogs (p = 0.03), between having dogs and in favor of neutering/spaying (p = 0.04) and considering neutering/spaying as the best control method (p = 0.02). The chances of thinking the best way to control stray dogs by neutering/spaying and adoption were almost 2.0 fold higher than other methods. In conclusion, the present study has provided indicators (education level, having dogs) for pet population control program assessment and effectiveness evaluation. Moreover, this study may serve as a warning on the real long-term effect of such programs, which should be periodically evaluated to identify necessary adjustments and/or improvements.

Demography of domestic dog population and its implications for stray dog abundance

Makenov, M. T., & Bekova, S. K. (2016). Demography of domestic dog population and its implications for stray dog abundance: a case study of Omsk, Russia. Urban Ecosystems, 1-14.

In cities of Russia, stray dog populations have been conserved for a long time, despite natural mortality and constant catching. We suggested that the overpopulation of owned dogs and their subsequent transition into stray dogs is a primary reason for the increase in the number of stray dogs. Information on owned dogs was obtained through a cross-sectional household survey of dogs owners in Omsk, Russia. Analysis of a vertical life table showed that the maximum mortality of owned dogs under 1 year of age was 53 %; in other age classes, the mortality was, on average, 5.6 %. Analysis of fecundity showed that 81 % of the owners do not mate their dogs; consequently, only 36 % of the adult females whelped at least once. Analysis of the Leslie matrix showed that the growth rate of the population of owned dogs was 1 % per year. This result shows minimum overpopulation. Previous dogs escaped or were lost or vanished in rare cases (approximately 0.5 %). However, in a megalopolis, even such low frequencies are significant (95 % CI: 1433–5473 individuals). Analyses of the demographic processes in a population of owned dogs showed that a transition from owned dogs to stray dogs exists. Overpopulation is not the key reason for the transition, but different accidents are: that is, pets are lost, run away, etc. The frequency of such events is small, but, because of the size of the city, the number of such dogs might be 10–39 % of the total number of stray dogs.

The influence of socio-demographic factors on free-roaming cat populations in an urban ecosystem in Israel

Finkler H, Hatna E, Terkel J (2011). The influence of neighbourhood socio-demographic factors on densities of free-roaming cat populations in an urban ecosystem in Israel. Wildlife Research 38(3): 235-243.

Context: Free-roaming cat populations are abundant in many urban ecosystems worldwide. Their management is necessary for reasons of public health, risk of wildlife predation and cat welfare related to their high densities. Trap–neuter–return (TNR) programs are now the main cat population control strategy in urban areas. However, the efficacy of such strategies is difficult to evaluate without more precise estimates of cat numbers and a better knowledge of anthropogenic influences on cat densities.

Aims: We aimed to estimate free-roaming cat population numbers and density in residential neighbourhoods in Tel Aviv, and to investigate population densities in relation to several socio-demographic factors.

Methods: We compared free-roaming cat population densities in terms of neighbourhood socio-economic status (SES), housing type, human density and percentage of residential and commercial areas. Five consecutive cat density surveys were carried out in eight residential neighbourhoods in Israel – four in northern Tel Aviv, characterised by high SES, and four in southern Tel Aviv, characterised by low SES. The photographic capture–recapture technique was used and abundance estimates were evaluated using the MARK program. Regression analyses examined the effect of socio-demographic factors on cat densities.

Key results: Neighbourhood socio-economic status significantly influenced kitten density and proportion of neutered cats in the total population: southern neighbourhoods had higher kitten densities and lower neutered cat proportions compared with northern neighbourhoods. Higher adult cat densities featured in mixed profile neighbourhoods of residential and commercial areas compared with solely residential neighbourhoods. Using the linear equation from the regression analysis the entire free-roaming cat population in Tel Aviv was extrapolated to 39 000 cats.

Conclusions: The results suggest that adult cat and kitten densities depend in part on socio-demographic factors, specifically on neighbourhood socio-economic status and the proportion of residential area.

Implications: Our findings in Tel Aviv may be used to improve cat management efforts, by focusing on neighbourhoods hosting higher cat densities; as well as to improve cat welfare by focusing on neighbourhoods with lower neutering rates and higher kitten densities. Finally, the current study may serve as a basis for studies in other cities with similar cat overpopulation problems.

Density and home range of feral cats in NW Australia

McGregor, H. W., Legge, S., Potts, J., Jones, M. E., & Johnson, C. N. (2015). Density and home range of feral cats in north-western Australia. Wildlife Research.

Context: Feral cats (Felis catus) pose a significant threat to biodiversity in Australia, and are implicated in current declines of small mammals in the savannas of northern Australia. Basic information on population density and ranging behaviour is essential to understand and manage threats from feral cats.

Aims: In this study, we provide robust estimates of density and home range of feral cats in the central Kimberley region of north-western Australia, and we test whether population density is affected by livestock grazing, small mammal abundance and other environmental factors.

Methods: Densities were measured at six transects sampled between 2011 and 2013 using arrays of infrared cameras. Cats were individually identified, and densities estimated using spatially explicit capture–recapture analysis. Home range was measured from GPS tracking of 32 cats.

Key results: Densities were similar across all transects and deployments, with a mean of 0.18 cats km^-2(range = 0.09–0.34 /km²). We found no evidence that population density was related to livestock grazing or abundance of small mammals. Home ranges of males were, on average, 855 ha (±156 ha (95% CI), n = 25), and those of females were half the size at 397 ha (±275 ha (95% CI), n = 7). There was little overlap in ranges of cats of the same sex.

Conclusions: Compared with elsewhere in Australia outside of semiarid regions, feral cats occur at low density and have large home ranges in the central Kimberley. However, other evidence shows that despite this low density, cats are contributing to declines of small mammal populations across northern Australia.

Implications: It will be very difficult to reduce these already-sparse populations by direct control. Instead, land-management practices that reduce the impacts of cats on prey should be investigated.

Free ranging and stray dog population in Omsk

Makenov, M. T., & Kassalb, B. Y. (2014). Study of Free-Ranging and Stray Dog Population in Omsk. Journal of Siberian Federal University. Biology, 1(7), 87-98.

The characteristics of free-ranging and stray dog population in Omsk City (Russia) were examined. The first section contains estimates of the population density in different urban areas. The average population density is 69 animals/km². Section 2 shows the sex ratio in dog population. The predominance of male over females has been registered with the overall sex ratio (male/female) equal 1:0,79. The section 3 characterizes the litter size for stray dogs. The average litter size is 4,3 pups per female.

Diet of the feral ca in central Australian grasslands during population cycles of its principal prey

Yip, S. J., Rich, M. A., & Dickman, C. R. (2014). Diet of the feral cat, Felis catus, in central Australian grassland habitats during population cycles of its principal prey. Mammal Research, 1-12.

Foraging theory predicts that animals should forage so as to maximize their net rate of energy gain or to minimize their risk of starvation. In situations where prey numbers fluctuate dramatically, theory predicts further that foragers will eat ‘optimal’ prey when it is abundant but expand their diet to include other prey types when the optimal prey is scarce; this is the alternative prey hypothesis. Here, we test this prediction by analyzing the diet of a mammalian predator, the feral house catFelis catus, during periods of scarcity and abundance of the long-haired rat Rattus villosissimus. We also investigate whether the body condition of feral cats differs during different stages of the prey population cycle. Feral cats were shot during culling operations in semi-arid grassland habitats in central Queensland, Australia, and the stomach contents later identified. We found that the body condition of feral cats did not differ between phases of the prey population cycle, but the diets of cats culled when long-haired rats were scarce were significantly more diverse than when this rodent was abundant. Rats comprised about 80 % of cats’ diet by volume and frequency of occurrence when they were present, whereas birds, reptiles and invertebrates comprised the bulk of the diet when rats were not available. We conclude that, whilst feral cats are often thought to be specialist predators, they may be better considered as facultative specialists that will shift their diet in predictable ways in response to changes in the abundance of primary prey.

Simulating free-roaming cat population management options in open demographic environments

Miller, P. S., Boone, J. D., Briggs, J. R., Lawler, D. F., Levy, J. K., Nutter, F. B., Margaret Slater, M. & Zawistowski, S. (2014). Simulating Free-Roaming Cat Population Management Options in Open Demographic Environments. PloS one, 9(11), e113553.

Large populations of free-roaming cats (FRCs) generate ongoing concerns for welfare of both individual animals and populations, for human public health, for viability of native wildlife populations, and for local ecological damage. Managing FRC populations is a complex task, without universal agreement on best practices. Previous analyses that use simulation modeling tools to evaluate alternative management methods have focused on relative efficacy of removal (or trap-return, TR), typically involving euthanasia, and sterilization (or trap-neuter-return, TNR) in demographically isolated populations. We used a stochastic demographic simulation approach to evaluate removal, permanent sterilization, and two postulated methods of temporary contraception for FRC population management. Our models include demographic connectivity to neighboring untreated cat populations through natural dispersal in a metapopulation context across urban and rural landscapes, and also feature abandonment of owned animals. Within population type, a given implementation rate of the TR strategy results in the most rapid rate of population decline and (when populations are isolated) the highest probability of population elimination, followed in order of decreasing efficacy by equivalent rates of implementation of TNR and temporary contraception. Even low levels of demographic connectivity significantly reduce the effectiveness of any management intervention, and continued abandonment is similarly problematic. This is the first demographic simulation analysis to consider the use of temporary contraception and account for the realities of FRC dispersal and owned cat abandonment.

Size estimation and demography of owned pets in NE ITaly

Capello, K., Bortolotti, L., Lanari, M., Baioni, E., Mutinelli, F., & Vascellari, M. (2014). Estimate of the size and demographic structure of the owned dog and cat population living in Veneto region (north-eastern Italy). Preventive Veterinary Medicine.

The knowledge of the size and demographic structure of animal populations is a necessary prerequisite for any population-based epidemiological study, especially to ascertain and interpret prevalence data, to implement surveillance plans in controlling zoonotic diseases and, moreover, to provide accurate estimates of tumours incidence data obtained by population-based registries. The main purpose of this study was to provide an accurate estimate of the size and structure of the canine population in Veneto region (north-eastern Italy), using the Lincoln-Petersen version of the capture-recapture methodology. The Regional Canine Demographic Registry (BAC) and a sample survey of households of Veneto Region were the capture and recapture sources, respectively. The secondary purpose was to estimate the size and structure of the feline population in the same region, using the same survey applied for dog population. A sample of 2,465 randomly selected households was drawn and submitted to a questionnaire using the CATI technique, in order to obtain information about the ownership of dogs and cats. If the dog was declared to be identified, owner's information was used to recapture the dog in the BAC. The study was conducted in Veneto Region during 2011, when the dog population recorded in the BAC was 605,537. Overall, 616 households declared to possess at least one dog (25%), with a total of 805 dogs and an average per household of 1.3. The capture-recapture analysis showed that 574 dogs (71.3%, 95% CI: 68.04% - 74.40%) had been recaptured in both sources, providing a dog population estimate of 849,229 (95% CI: 814,747 - 889,394), 40% higher than that registered in the BAC. Concerning cats, 455 of 2,465 (18%, 95%CI: 17% - 20%) households declared to possess at least one cat at the time of the telephone interview, with a total of 816 cats. The mean number of cats per household was equal to 1.8, providing an estimate of the cat population in Veneto region equal to 663,433 (95%CI: 626,585 - 737,159). The estimate of the size and structure of owned canine and feline populations in Veneto region provide useful data to perform epidemiological studies and monitoring plans in this area.

Dog ecology and demography in Machakos District, Kenya

Kitala, P., McDermott, J., Kyule, M., Gathuma, J., Perry, B., & Wandeler, A. (2001). Dog ecology and demography information to support the planning of rabies control in Machakos District, Kenya. Acta Tropica, 78(3), 217-230.

A study of 150 dog-owning households from six randomly selected sublocations was conducted in Machakos District, Kenya. Initially, all households were visited to collect information on dog ecology and demography based on WHO guidelines and to collect serum for rabies antibody detection. A second visit was made 1 year later, to obtain follow-up data on births, deaths, dog movements and other events since the first visit. Dog ownership was common, with a range of 53–81% (mean=63%) of households owning dogs in the six sublocations. Dog density for the five more rural sublocations ranged from 6 to 21 dogs  km^-2 and for the peri-urban sublocation was 110 dogs  km^-2. The dog population was estimated to be growing at 9% p.a. (95% C.I. 4–14%). This growth was a function of very high fecundity (1.3 females per female per year) more than compensating for high mortality, particularly among females. Life expectancy from birth was 3.5 years for males and 2.4 years for females. Half the dogs at any one time were less than 1 year of age. All dogs, by design of the study, were owned. Of these, 69% were never restricted and roamed freely to forage for food and mix with other dogs. Only a small proportion of dogs (5%) were fed commercial dog food. Most households reported observing dogs scavenging their garbage, including: their own dogs (81%), their neighbours’ dogs (75%) and unknown dogs (45%). Only 29% of dogs at least 3 months of age were reported to be vaccinated against rabies. The proportion vaccinated varied widely between sublocations (5–68%); 48% of dogs reportedly vaccinated had detectable antibodies, 31% at or above levels considered to indicate seroconversion. The proportion of dogs with detectable antibodies declined according to the time since last vaccination (55% if vaccinated ≤1 year, 47% ≤2 years and 36% >2 years); 20% of dogs reported not to have been vaccinated had detectable rabies antibody. Compared to other dog populations in rural eastern and southern Africa, Machakos District has a high density of dogs. The Machakos dog population is growing, highly dynamic, poorly supervised and inadequately vaccinated against rabies. The main implication for rabies control is that adequate vaccination coverage is unlikely to be achieved, even under optimal delivery, using the current strategy of annual vaccination of dogs older than 3 months.

Reduction of feral cat colony size following hysterectomy of adult female cats

Mendes-de-Almeida, F., Remy, G. L., Gershony, L. C., Rodrigues, D. P., Chame, M., & Labarthe, N. V. (2011). Reduction of feral cat (Felis catus Linnaeus 1758) colony size following hysterectomy of adult female cats. Journal of feline medicine and surgery, 13(6), 436-440.

The size of urban cat colonies is limited only by the availability of food and shelter; therefore, their population growth challenges all known population control programs. To test a new population control method, a free-roaming feral cat colony at the Zoological Park in the city of Rio de Janeiro was studied, beginning in 2001. The novel method consisted of performing a hysterectomy on all captured female cats over 6 months of age. To estimate the size of the colony and compare population from year to year, a method of capture-mark-release-recapture was used. The aim was to capture as many individuals as possible, including cats of all ages and gender to estimate numbers of cats in all population categories. Results indicated that the feral cat population remained constant from 2001 to 2004. From 2004 to 2008, the hysterectomy program and population estimates were performed every other year (2006 and 2008). The population was estimated to be 40 cats in 2004, 26 in 2006, and 17 cats in 2008. Although pathogens tend to infect more individuals as the population grows older and maintains natural behavior, these results show that free-roaming feral cat colonies could have their population controlled by a biannual program that focuses on hysterectomy of sexually active female cats.

Urban cat density more depending on shelter than on food

Calhoon, R.E. & Haspel, C. 1989. Urban Cat Populations Compared by Season, Subhabitat and Supplemental Feeding. Journal of Animal Ecology. 58(1): 321–328.

(1) Population densities of free-ranging cats were compared in two contiguous urban subhabitats, in three seasons, and in response to supplemental feeding.

(2) One subhabitat, characterized by voluminous, poorly contained refuse, and many abandoned buildings, supported 4.88 +- 0.82 cats ha-1 (mean +- S.D.), which differed significantly from the 2.03 +- 0.2 cats/ha supported by the other subhabitat (partial refuse containment, few abandoned buildings). 

(3) Neither season nor supplemental feeding had a significant effect on population density. 

(4) The distribution of individuals within the study area varied with the availability of shelter and was not dependent upon food.

Chapter 2: Population structure and management

Koch, K., Algar, D., & Schwenk, K. (2014). Population structure and management of invasive cats on an Australian Island. Genetic diversity and phylogeography of Australian feral cats: 42.

Invasive predators have a major impact on endemic island species; therefore, information about invasion dynamics are essential for implementing successful control measures. The introduction of feral cats onto Dirk Hartog Island, Western Australia, has had devastating effects, with presumably 10 of 13 native terrestrial mammal species being lost because of predation. Since detailed records of historical introduction events were lacking, we analysed genetic variation of the current population to gain information about past invasion dynamics and current gene-flow patterns. We analyzed the genetic structure and diversity of feral cats on the island and 2 adjacent mainland populations (Peron Peninsula and Steep Point). Analysis of mitochondrial DNA (ND5 and ND6) showed 2 primary haplotypes that we attribute to 2 main introduction events. Pairwise G’’ST values indicated high connectivity on the island but some isolation to the mainland populations. Mitochondrial and nuclear data showed no evidence for genetic differentiation of island and mainland populations; however, kinship analyses rejected evidence for on-going immigration of members of the current cat populations. Overall, our data suggested that gene flow following the main introduction events ceased some years ago. Because current island populations appear to be reproductivelyisolated from mainland populations, a sufficiently large-scale eradication measure might successfully diminish feral cat populations long-term.

The demography of free-roaming dog populations and applications to disease and population control

Morters, M. K., McKinley, T. J., Restif, O., Conlan, A. J. K., Cleaveland, S., Hampson, K.,
Whay, H. R , Damriyasa, I M.  & Wood, J. L. N. (2014). The demography of free‐roaming dog populations and applications to disease and population control. Journal of Applied Ecology.


Understanding the demography of domestic dog populations is essential for effective disease control, particularly of canine-mediated rabies. Demographic data are also needed to plan effective population management. However, no study has comprehensively evaluated the contribution of demographic processes (i.e. births, deaths and movement) to variations in dog population size or density, or determined the factors that regulate these processes, including human factors.

We report the results of a three-year cohort study of domestic dogs, which is the first to generate detailed data on the temporal variation of these demographic characteristics. Two communities were monitored at each study site in rabies-endemic areas and where the majority of dogs were free-roaming: Bali, Indonesia and Johannesburg, South Africa. None of the four communities had been engaged in any dog population management interventions by local authorities or animal welfare organizations. All identified dogs in the four communities were monitored individually throughout the study.

We observed either no population growth or a progressive decline in population size during the study period. There was no clear evidence that population size was regulated through environmental resource constraints. Rather, almost all of the identified dogs were owned and fed regularly by their owners, consistent with population size regulated by human demand. Finally, a substantial fraction of the dogs originated from outside the population, entirely through the translocation of dogs by people, rather than from local births. These findings demonstrate that previously reported growth of dog populations is not a general phenomenon, and challenge the widely held view that free-roaming dogs are unowned and form closed populations.

Synthesis and applications. These observations have broad implications for disease and population control. The accessibility of dogs for vaccination and evaluation through owners and the movement of dogs (some of them infected) by people will determine the viable options for disease control strategies. The impact of human factors on population dynamics will also influence the feasibility of annual vaccination campaigns to control rabies and population control through culling or sterilisation. The complex relationship between dogs and people is critically important in the transmission and control of canine-mediated rabies. For effective management, human factors must be considered in the development of disease and population control programmes.

Modelling feral cat population under TNR

Lee, L. E., Robl, N., Bugman, A. M., Nguyen, A. T., Lammers, B., Fisher, T. L., Weimer, H., Lenhart, S. & New Jr, J. C. (2014). Modeling Feral Cat Population Dynamics in Knox County, TN. University of Tennessee Honor Thesis Projects.

Feral cats (Felis catus) are recognized as a problem internationally due to their negative impact on wildlife and potential to spread infectious disease to people and other animals. Trap-neuterreturn (TNR) programs are employed in many areas to control feral cat populations as a humane method, and this approach is used on a limited basis in Knox County, Tennessee. Despite the frequent use of TNR as a strategy, its effectiveness remains controversial. The objective of this mathematical model is to predict the impact of selected strategies on the population of feral cats. The model with three age classes predicts the population over a period of 5 years in one month time steps. TNR rates are varied to investigate the effects of targeting spay/neuter programs seasonally, and such targeting predicts a measurable decline in feral cat population growth over a five year period. Targeting TNR intervention at adult females during the time prior to mating season in highly populated feral colonies may further decrease the population. These results suggest a more efficacious strategy than non-targeted TNR programs.

Demography and ecology of free-ranging dogs in North America

Daniels, T. J., & Bekoff, M. (1989). Population and social biology of free-ranging dogs, Canis familiaris. Journal of Mammalogy, 70 (4) 754-762.

Population size and density, age structure, survivorship patterns, sex ratios, and social organization of urban, rural, and feral dog (Canis familiaris) populations were examined in Cd. Juarez, Mexico (urban site) and on the Navajo reservation (rural and wild sites) between June 1983 and December 1984. Urban and rural dogs were less social than expected whereas feral dogs characteristically lived in packs. Seasonal variation in the structure of feral dog packs was influenced by reproduction, both directly (pups born into the pack) and indirectly (pregnant females may temporarily emigrate form the pack to give birth).



Daniels, T. J., & Bekoff, M. (1989). Spatial and temporal resource use by feral and abandoned dogs. Ethology, 81(4), 300-312.

We compared spatial and temporal patterns of resource use by feral and abandoned domestic dogs (Canis familiaris) on the Navajo reservation in Arizona and New Mexico. Community dumps provide locally abundant food resources utilized both by feral dogs and dogs abandoned at the dump site. Although population parameters were much the same for feral and abandoned dogs, the use of space varied distinctly and reflected behavioral differences in the way each population responded to the absence of human control, the need to acquire food, and the developmental state of pups. Temporal use of resources by feral dogs varied seasonally with the age of pups in one pack, but not in a second pack. Priority of access to local resources may be influenced by aggressive interactions among dogs at a dump. Barking may serve to warn dogs already present at a dump that competitors have arrived.

Reducing feral cat threats to native wildlife in Hawai`i

Hess, S. C., H. Hansen, and P. C. Banko. 2007. Reducing feral cat threats to native wildlife in Hawai`i. Hawai`i Cooperative Studies Unit Technical Report HCSU-010. University of Hawai`i at Hilo. 102 pp., incl. 14 figures, & 19 tables.

We documented the diet of feral cats (Felis catus) on Kīlauea and Mauna Loa within Hawai`i Volcanoes National Park (HAVO), determined the incidence of three feline diseases on Mauna Kea, studied feral cat home range, developed and tested trap-signaling devices, tested food-based baits and attractants, analyzed feral cat population dynamics using genetic techniques, and developed an adaptive strategy for reducing predation on endangered Hawaiian birds.

We documented the diet of feral cats by analyzing the contents of 42 digestive tracts from Kīlauea and Mauna Loa in Hawai`i Volcanoes National Park. Small mammals, invertebrates, and birds were the most common prey types consumed by feral cats. Birds occurred in 27.8–29.2% of digestive tracts. The total number of bird, small mammal, and invertebrate prey differed between Kīlauea and Mauna Loa. On Mauna Loa, significantly more (89%) feral cats consumed small mammals, primarily rodents, than on Kīlauea Volcano (50%). Mice (Mus musculus) were the major component of the feral cat diet on Mauna Loa, whereas Orthoptera were the major component of the diet on Kīlauea. We recovered a mandible set, feathers, and bones of an endangered Hawaiian Petrel (Pterodroma sandwichensis) from a digestive tract from Mauna Loa. This specimen represents the first well-documented endangered seabird to be recovered from the digestive tract of a feral cat in Hawai`i and suggests that feral cats prey on this species.

We determined prevalence to feline immunodeficiency virus (FIV) antibodies, feline leukemia virus (FeLV) antigen, and Toxoplasma gondii antibodies in feral cats on Mauna Kea Hawai`i from April 2002 to May 2004. Six of 68 (8.8%) and 11/68 (16.2%) were antibody positive to FIV and antigen positive for FeLV, respectively; 25/67 (37.3%) were seropositive to T. gondii. Antibodies to FeLV and T. gondii occurred in all age and sex classes, but FIV occurred only in adult males. Evidence of previous or current infections with two of these infectious agents was detected in eight of 64 cats (12.5%). Despite exposure to these infectious agents, feral cats remain abundant throughout the Hawaiian Islands.

Feral cats in dry subalpine woodland of Mauna Kea, Hawai`i, live in low density and exhibit some of the largest reported home ranges in the literature. While 95% fixed kernel home range estimates for three females averaged 772 ha, four males averaged 1,418 ha, and one male maintained a home range of 2,050 ha. Mean daily movement rates between sexes overlapped widely and did not differ significantly (P = 0.083). Log-transformed 95% kernel home ranges for males were significantly larger than those of females (P = 0.024), but 25% kernel home ranges for females were larger than those of males (P = 0.017). Moreover, logtransformed home ranges of males were also significantly larger than those of females in this and seven other studies from the Pacific region (P = 0.044). Feral cats present a major threat to endangered Hawaiian birds, but knowledge of their ecology can be used for management by optimizing trap spacing and creating buffer zones around conservation areas.

Frequent checks of live traps require enormous amounts of labor and add human scents associated with repeated monitoring which may reduce capture efficiency. To reduce efforts and increase efficiency, we developed a trap-signaling device with long-distance reception, durability in adverse weather, and ease of transport, deployment, and use. Modifications from previous designs include a normally-open magnetic switch and a mounting configuration to maximize reception. The system weighed < 225 g, was effective ≤ 17.1 km, and failed in < 1% of trap-nights. Employing this system, researchers and wildlife managers may reduce the amount of effort checking traps while improving the welfare of trapped animals.

Successful feral cat control programs require effective baits and lures. Non-targets may interfere with trapping efforts by rapidly consuming bait before feral cats encounter traps, necessitating frequent bait replacement. We compared the effectiveness of baits and lures by analyzing capture rates of feral cats and non-targets and monitoring animal visits to bait stations with remotely-triggered cameras. We tested four different baits and attractants: canned cat food, sardines, catnip, and a bait sausage that we formulated from pork and fat. We trapped for a total of 3,389 trap nights and captured 35 feral cats. There were 323 incidences of trap interferences, reducing the effective trap nights (ETN) to 3,225. The primary cause of trap interference was feral pigs rolling over traps (n = 185, 57.3% of interferences). The primary non-target species captured were small Indian mongooses (n = 74, 22.9% of interferences). Overall, more cats and mongooses were captured using sardines, although the catch frequencies were not dependent on the bait type used. We obtained photographs of 1,476 small mammals at the bait stations. Mongooses were the principal mammals photographed (n = 939, 69.5% of pictures). We also obtained 398 photographs of rats (29.5%) and 9 (0.7%) of mice. Feral cats were photographed only 5 (0.4%) times. We found strong differences between mongooses, rodents, and cats photographed at the four bait types. Sardines were the most visited bait type (n = 641, 47.4% of photographs). Pork sausage and cat food accounted for 383 (28.3%) and 322 (23.8%) visits while catnip had only 67 (5.0%) visits. Feral cats were photographed only at sardine bait. Mongooses were attracted primarily to  sardines (49.3%). Pork sausage was the most attractive bait to rats, accounting for 44.5% of photographs. Due to the high rate of non-target interference, other attractants need to be tested for successful feral cat control programs.

Population genetics can provide information about the demographics and dynamics of invasive species that is beneficial for developing effective control strategies. We studied the population genetics of feral cats on Hawai`i Island by microsatellite analysis to evaluate genetic diversity and population structure, assess gene flow and connectivity among three populations, identify potential source populations, characterize population dynamics, and evaluate sex-biased dispersal. High genetic diversity, low structure, and high number of migrants per generation supported high gene flow that was not limited spatially. Migration rates revealed that most migration occurred out of West Mauna Kea. Effective population size estimates indicated increasing cat populations despite control efforts. Despite high gene flow, relatedness estimates declined significantly with increased geographic distance and Bayesian assignment tests revealed the presence of three population clusters. Genetic structure and relatedness estimates indicated male-biased dispersal. Mauna Kea may be a source population that can be targeted for control. However, recolonization seems likely given the great dispersal ability that may not be inhibited by barriers such as lava flows. Genetic monitoring will be necessary to assess the effectiveness of future control efforts.

Despite the long history of feral cats in Hawai`i, there has been little research to provide strategies to improve control programs and reduce depredation on endangered species. Our objective was to develop a predictive model to determine how landscape features on Mauna Kea such as habitat, elevation, and proximity to roads affect the number of feral cats captured at each trap. We used log-link generalized linear models and QAICc model ranking criteria to determine the effect of these factors. We found that the number of cats captured per trap was related to trapping effort, habitat type, and whether traps were located on the West or North Slope of Mauna Kea. We recommend an adaptive management strategy to minimize trapping interference by non-target small Indian mongoose (Herpestes auropunctatus) with toxicants, to focus trapping efforts in māmane (Sophora chrysophylla) habitat on the West slope of Mauna Kea, and to cluster traps near others that have previously captured multiple cats.

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. 

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 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.

Ecology of a feral cat population in rural Northern Italy

Genovesi, P., Besa, M., & Toso, S. (1995). Ecology of a feral cat Felis catus population in an agricultural area of northern Italy. Wildlife Biology, 1: 233-237.

The ecology of a feral cat population in an intensively cultivated region of northern Italy was studied. The study area is a land accretion territory, reclaimed in the early 1970s, characterised by the absence of any food source of human origin (e.g. garbage dumps, farms, houses) and surrounded by a continuous irrigation channel that is likely to limit immigration/emigration of cats. The cat population was censused for two successive years using the sighting-resighting method; spacing patterns were studied by means of radio-telemetry; hunting behaviour was assessed by observation. Feral cats avoided any direct contact with humans, and reproduced in the wild. The density of the population remained stable throughout the study period. Turnover appeared very high, and was remarkably higher than that of cats regularly fed by humans. Very low densities, large home range sizes, solitary habits, territorial patterns similar to those of the wildcat, seasonal parturition, and prevalence of hunting activity were found. We speculate that these patterns are related to the peculiar conditions of resource availability and dispersion in the study area. Our results indicate that feral cats, even in agricultural areas and in the absence of any food provided by humans, have solitary habits and low densities, thus confirming a key role of resource availability and dispersion on the ecology of carnivores.