Prospects for domestic and feral cat management on an inhabited tropical island

Dias, R. A., Abrahão, C. R., Micheletti, T., Mangini, P. R., de Oliveira Gasparotto, V. P., de Jesus Pena, H. F., ... & Silva, J. C. R. 2017. Prospects for domestic and feral cat management on an inhabited tropical island. Biological Invasions, 1-15.

Cat management campaigns have been implemented on several islands worldwide. However, few successful campaigns have occurred on permanently inhabited islands. Cats are known for causing severe impacts on the native insular fauna, posing an important threat to biodiversity. Moreover, this species is also responsible for zoonosis maintenance and transmission. A thorough understanding of cat population structure (e.g., supervised vs. unsupervised) is strongly suggested as a management action on inhabited islands, as it might promote more efficient and effective management of this species. Fernando de Noronha is an archipelago in the tropical Atlantic Ocean. The total cat population on the main island was estimated at 1287 animals, most of them supervised and subsidized around inhabited areas. Free-roaming cats currently threaten the endemic terrestrial fauna of Fernando de Noronha, and the cat density found by the present work is among the highest ever recorded on an island. Using population dynamic simulations, the long-term effects of reproduction control and removal of cats from the archipelago were assessed. Removal of cats was also suggested as a necessary management strategy to achieve negative population growth. In addition, it was more cost-effective than reproduction control. However, applying both removal and sterilization strategies to this population resulted in a higher population decrease than removal alone. For these reasons, a combination of reproductive control and cat eradication should be implemented in Fernando de Noronha.

Other environmental factors affects more Island foxes diet than competition with feral cats

Cypher, B.L. , Kelly E.C., Ferrara, F.J., Drost C.A., Westall, T.L. & Hudgens, B.R. 2017. Diet patterns of island foxes on San Nicolas Island relative to feral cat removal. Pacific Conservation Biology 23(2) 180-188

Island foxes (Urocyon littoralis) are a species of conservation concern that occur on six of the Channel Islands off the coast of southern California. We analysed island fox diet on San Nicolas Island during 2006–12 to assess the influence of the removal of feral cats (Felis catus) on the food use by foxes. Our objective was to determine whether fox diet patterns shifted in response to the cat removal conducted during 2009–10, thus indicating that cats were competing with foxes for food items. We also examined the influence of annual precipitation patterns and fox abundance on fox diet. On the basis of an analysis of 1975 fox scats, use of vertebrate prey – deer mice (Peromyscus maniculatus), birds, and lizards – increased significantly during and after the complete removal of cats (n = 66) from the island. Deer mouse abundance increased markedly during and after cat removal and use of mice by foxes was significantly related to mouse abundance. The increase in mice and shift in item use by the foxes was consistent with a reduction in exploitative competition associated with the cat removal. However, fox abundance declined markedly coincident with the removal of cats and deer mouse abundance was negatively related to fox numbers. Also, annual precipitation increased markedly during and after cat removal and deer mouse abundance closely tracked precipitation. Thus, our results indicate that other confounding factors, particularly precipitation, may have had a greater influence on fox diet patterns.

Bait delivery for cats using drons

Johnston, M., McCaldin, G., & Rieker, A. (2016). Assessing the availability of aerially delivered baits to feral cats through rainforest canopy using unmanned aircraft. Journal of Unmanned Vehicle Systems, 4(4), 276-281.

At least eight threatened wildlife species are at direct risk from predation by cats (Felis catus) on Christmas Island (Director of National Parks. 2014. Christmas Island biodiversity conservation plan. Canberra. Australia: Department of the Environment.). A range of strategies are now being used to manage cats across the island, including responsible ownership methods for domestic cats and lethal control tools to remove feral cats outside the township area. Unmanned aerial vehicles (UAVs) were used to drop non-toxic baits through the rainforest canopy to assess whether aerial baiting could be undertaken successfully on the island. Ground crews located 88% of baits, indicating that sufficient baits would be accessible to feral cats if broad-scale aerial baiting was to be undertaken in the future.

Cats and Tropci birds

Boeken, M. (2016). Breeding success of Red-billed Tropicbirds Phaethon aethereus on the Caribbean island of Saba. Ardea, 104(3), 263-271.

In 2011 and 2012 the breeding success of Red-billed Tropicbirds Phaethon aethereus mesonauta was monitored on Saba, a 13-km2 island in the Caribbean Netherlands. The two colonies on the south and south-west side of the island both contain approximately 100–300 nests; breeding success was zero at these sites, due to predation of newly hatched chicks by Feral House Cats. In the single large colony of Old Booby Hill (estimated to contain approximately 1000 nests) on the east side of the island, rates of predation were lower, resulting in a breeding success (survival from laying until fledging, as far as observed) of 65%. Calculations of daily survival of eggs and chicks following Mayfield, resulted in a nesting success of 48% per pair. I conservatively estimated the size of the Saba breeding population to be at least 1300–1500 pairs, which is larger than the previous estimate of 750–1000 pairs. Potentially, the number of breeding pairs may be as high as 1850 pairs.

Ecology of feral cats on a Tasmanian Island

Hayde, K. A. (1992). Ecology of the feral cat Felis catus on Great Dog Island (Doctoral dissertation, University of Tasmania).

Aspects of the ecology of feral cats on Great Dog Island, Bass Strait, were investigated from May to September 1991. Population structure and dynamics, morphology and phenotypes, condition and gastro-intestinal parasites and diet were studied. A culled sample of 189 feral cats displayed a male: female ratio of 1:1 and indicated a pre-eradication density of at least 56.9 cats/km2• Juveniles and sub-adults made up 44.9% of the population. A breeding season was inferred by kitten age and by changes through time in the population structure. Approximate life expectancy was estimated to be 73-84 months for males and 85-96 months for females. Counting cementum annuli in the teeth was shown to be an effective method of age determination. The length and weight of male and female feral cats of Great Dog Island was comparable to that of feral cats found on the mainland Australian. However, a decline in the weight of females between autumn and winter suggested the occurrence of a seasonal nutritional stress. The relationship between age and length in adult males suggests that greater length offers an advantage to longevity. The presence of seven mutant pelagerelated genes, in addition to the wild type, indicated a comparatively high degree of genetic diversity within the feral cat population of Great Dog Island. The long hair allele is probably being selected against as juveniles suffer high mortality. The expression of the inhibitor allele is bias toward males. No significant relationships were found to occur between coat colour and weight or length. The analysis of gut contents showed that a total of 26 species were ingested: 2 bird, 1 mammal, 5 reptile and 18 arthropod species. The gut of 16 cats were either empty or contained only residual food stuffs. Most cats had soil and plant matter in the gut. There was no evidence of cannabalism and no human refuse was present. It is likely that some artht:opod prey were excavated. There was no advantage in age or body size in obtaining prey species. Generally, the coat skin and tooth condition of cats on Great Dog Island was very good. The nutritional condition (fat deposits) of cats suggested that cats were generally in good condition in autumn. Both males and females underwent a large decline in fat reserves from autumn to winter and reserves were further depleted as winter progressed. This resulted in the general nutiitional condition of the winter cats being poor. Gastro-intestinal parasites present were Taenia taeniaeformis, Toxocara cati and Cylicospirura felineus . Parasite infestation was biased toward females. Loss of condition did not generally result in increased susceptibility to parasite infestation. This was instead better explained as a response to diet and climate.

Feral cats driving the regional extinction of a threatened rodent in northern Australia

Davies, H. F., McCarthy, M. A., Firth, R. S., Woinarski, J. C., Gillespie, G. R., Andersen, A. N., ... & Murphy, B. P. (2016). Top‐down control of species distributions: feral cats driving the regional extinction of a threatened rodent in northern Australia. Diversity and Distributions.

Aim

To investigate whether feral cats influence the distribution of Australia's largest remnant population of the threatened brush-tailed rabbit-rat Conilurus penicillatus and examine whether they influenced the extinction probability of C. penicillatus over a 15-year period (2000–2015).

Location

Melville Island, northern Australia.

Methods

In 2015, small mammal surveys were conducted at 88 sites across Melville Island, 86 of which had previously been surveyed in 2000–2002. We used single-season occupancy models to investigate correlates of the current distribution of C. penicillatus and dynamic occupancy models to investigate correlates of C. penicillatus local extinction.

Results

Our results show that C. penicillatus, which once occurred more widely across the island, is now restricted to parts of the island where feral cats are rarely detected and shrub density is high. Our results suggest that feral cats are driving C. penicillatus towards extinction on Melville Island, and hence have likely been a significant driver in the decline of this species in northern Australia more broadly. The impact of feral cats appears to be mitigated by vegetation structure.

Main conclusions

The ongoing development and implementation of methods to effectively reduce feral cat densities, coupled with the management of landscape processes to maintain shrub density, through fire management and the removal of large exotic herbivores, will contribute substantially to conserving this threatened species. This study demonstrates that the distribution of species can be strongly influenced by top-down factors such as predation, thereby highlighting the importance of including biotic interactions when investigating the distribution of predation-susceptible species.

No evidence of dietary shift by native predators in sympatry with feral cats

Phillips, R. B., Winchell, C. S., & Schmidt, R. H. (2007). Dietary overlap of an alien and native carnivore on San Clemente Island, California. Journal of Mammalogy, 88(1), 173-180.


Predation by feral cats (Felis catus) is recognized as a major threat to native fauna worldwide, but the competitive effects of cats on native species have not been extensively studied. Cats occur on San Clemente Island, California, in sympatry with endemic island foxes (Urocyon littoralis clementae). We examined diets of cats and island foxes between years, seasons, and habitats to assess the potential for resource competition between the 2 species. Analysis of 602 cat and 958 fox feces revealed a high level of dietary overlap (O = 0.93) and relatively narrow niche breadths for both species (Bstandard Fox = 0.37; Bstandard Cat = 0.49). Despite the overlap in diet, cats and foxes appear to partition prey resources. Cats consume approximately equal proportions of arthropod (47.9%) and vertebrate (44.2%) prey, the latter primarily rodents (29.2%) and lizards (12.9%). In contrast, foxes appear to rely more on arthropods (57.7%), with plants (20.5%) and vertebrates (21.6%) occurring in lower, but roughly equal frequencies. Season appeared to have little effect on diet; however, diet did vary between habitats and years for both species. Diets of cats on San Clemente Island are consistent with those from other studies. We found no evidence of a dietary shift by foxes that were in sympatry with cats.

Progress in the eradication of the feral cat and recovery of the native fauna on Socorro Is

Ortiz-Alcaraz, A., Aguirre-Muñoz, A., Arnaud, G., Galina-Tessaro, P., Rojas-Mayoral, E., Méndez-Sánchez, F., & Ortega-Rubio, A. (2017). Progress in the eradication of the feral cat (Felis catus) and recovery of the native fauna on Socorro Island, Revillagigedo Archipelago, Mexico. Therya, 8(1).

Socorro Island, in the Revillagigedo Archipelago, has the highest number of endemisms of any Mexican island. It provides habitat for 117 vascular plants, 26 % of which are endemic to the island. Also endemic to the island are one reptile and eight terrestrial bird species. However, the local ecosystem has been heavily degraded by exotic mammals over the past 140 years. The feral sheep (Ovis aries) has contributed to a 30% loss in habitat based on the island’s surface area. Another serious threat is the feral cat (Felis catus), which has severely impacted the island’s bird communities and the endemic Socorro tree lizard (Urosaurus auriculatus). Together, feral sheep and cats are responsible for the extinction in the wild of the Socorro dove (Zenaida graysoni) and the Socorro Elf Owl (Micrathene whitneyi graysoni), and pose a serious threat for other vulnerable species, such as the Townsend’s shearwater (Puffinus auricularis). The feral sheep was completely eradicated in 2012, which resulted in a rapid and remarkable recovery of the local vegetation cover. The eradication of the feral cat has been a complex issue to undertake due to the large size and topographical complexity of Socorro Island. In 2011 Grupo de Ecología y Conservacion de Islas, A. C. (GECI) started a feral cat control program, which scaled up into an eradication campaign. Here we report on the progress of the eradication campaign between 2011 and 2015, and provide a first assessment of the recovery of the native fauna. Beginning in 2011, camera traps were used to estimate cat abundance. Leg-hold and lethal traps were used to capture feral cats, some of them mounted with telemetry devices that alerted when traps were activated. Native vertebrates were monitored to confirm the positive effects derived from cat control efforts. By July 2015, 413 cats were dispatched using soft leg-hold and lethal traps, with a combined effort of 22,706 trap-nights. To date (mid-2016), cat abundance has decreased significantly, with cats being completely absent for several years in different areas of the island. The abundance of the endemic Socorro Island tree lizard and terrestrial birds has increased thanks to significant progress. Completing this important conservation action requires an increase in trapping efforts and the use of detection dogs, combined with night hunting. We estimate that the eradication of the feral cat will be completed by early 2017, after which the absence confirmation phase will begin.

Reduction in the capture success (%) of feral cats in the rainy and dry seasons from 2012 to 2015.

Drons to deliver baits to control feral

Johnston, M., McCaldin, G., & Rieker, A. (2016). Assessing the availability of aerially delivered baits to feral cats through rainforest canopy using unmanned aircraft. Journal of Unmanned Vehicle Systems, 4(4), 276-281.
At least eight threatened wildlife species are at direct risk from predation by cats (Felis catus) on Christmas Island (Director of National Parks. 2014. Christmas Island biodiversity conservation plan. Canberra. Australia: Department of the Environment.). A range of strategies are now being used to manage cats across the island, including responsible ownership methods for domestic cats and lethal control tools to remove feral cats outside the township area. Unmanned aerial vehicles (UAVs) were used to drop non-toxic baits through the rainforest canopy to assess whether aerial baiting could be undertaken successfully on the island. Ground crews located 88% of baits, indicating that sufficient baits would be accessible to feral cats if broad-scale aerial baiting was to be undertaken in the future.

Proposed management plan for cats and black rats on Christmas Island.

Algar, D., & Johnston, M. (2010). Proposed management plan for cats and black rats on Christmas Island. Government of Western Australia Department of Environment and Conservation.

Proposed management plan for cats and black rats on Christmas Island 1Report outline The impact of cats on the biodiversity of Christmas Island is of concern to land management agencies and the broader  community.  Domestic  and  stray  cats  reside  in  the  residential,  commercial  and  light industrial  area while a population of feral cats exists across the rest of the island (i.e. mining lease, national park and other  Crown  land).  Concern  has  been  raised  regarding  the  threat  that  all ‘classes’  of  cats  present  to  the  viability  of  a  number  of  endangered  fauna  populations. Additionally,  previous  research  has  demonstrated  that  the  cats  on  the  island  also  have  a  very high  prevalence  of  Toxoplasmosis, a  parasite  that  can  lead  to  serious  human  health complications.The  management  of  cats  on  the  island  is  a  complex  task  as reduction/eradication in cat numbers alone could lead to changes in the abundance of other exotic species populations, especially  the  introduced  black  rat  which  then  may  threaten  wildlife  species  and  also  have disease implications.  

Land  management  agencies  on  Christmas  Island  have  commissioned  this report  which  describes  the  rationale and development of a long-term cat and black rat management and eradication plan to mitigate the environmental  and  social  impacts  of  cats  and  black  rats across  all  land  tenures  (shire-managed  lands,  Crown land including mine leases and Christmas Island National Park).   

The  report  provides  a  background  to  the  threats  and  impacts  of  cats and  black  rats  on  the  island’s  natural  and  social  environment,  including  wildlife  predation  and disease  threats  to  wildlife  and  human  health.  It  documents  previous  reports  in  relation  to impact  and  management  of  cats  and  black  rats  on  Christmas  Island.  The  current  local  cat management  laws  (Shire  of  Christmas  Island  Local  Law  for  the  Keeping  and  Control of Cats 2004) under the Local Government Act 1995 (WA) (CI) are evaluated (see Appendix 1) with the aim of limiting domestic and stray cat impact on the iconic native fauna of Christmas Island, promoting responsible cat ownership, compliance and enforcement of cat management laws and measures required to implement a ‘last cat policy’ for the Island.  

Cat  and  rodent  eradication  programs  and strategies  developed  and/or  implemented  by other conservation  agencies and local governments, particularly for islands are evaluated for their utility on Christmas Island. A strategy  is recommended that  provides  a staged approach  to  cat  and black  rat  management and  control  leading to eradication of one or both target species. Techniques, actions and priorities are described as are recommendations   of   where   additional   research   is   required.   A   monitoring   program   to   measure   the   effectiveness  of  the  strategy  is  reported which  enables  investigation  of  the potential  relationships  between  cats  and  their  invasive species  prey,  including  rodents  and centipedes,  and  strategies  to  address  any  negative environmental or social impacts of cat control. Monitoring requirements to maintain a cat and black rat free status including quarantine requirements to prevent, detect and quickly manage, new incursions are also discussed. 

Timelines and resource requirements to undertake this program are provided in Appendix 2. 

Human-cat relationship in an oceanic biosphere reserve

Medina, F. M., Nogales, M., Farnworth, M. J., & Bonnaud, E. (2016). Human-cat relationship in an oceanic biosphere reserve: The case of La Palma Island, Canary archipelago. Journal for Nature Conservation.

Removal of feral cats from island environments is a useful mechanism by which their ecological impact on endangered species can be reduced or ended. Nevertheless, because cats are anthropogenic in their origins, social perceptions of management practices play a large role in their implementation. Four-hundred questionnaires were delivered (386 were returned) with 100 going to each of the following: local residents; environmental workers; tourists; and, hunters. Questions explored respondents’ knowledge about island biodiversity and invasive species as well as attitudes towards cat population management methods. Habitat destruction and introduction of invasive species were considered the main threats for the conservation of island biodiversity. Most respondents considered cats to have a negative impact on biodiversity and sterilization campaigns were considered most appropriate for cat population control. Several free sterilization campaigns have been conducted in La Palma Island Biosphere Reserve in order to reduce free-ranging cats and were well received by local people. This research, which combined concepts of management, ecology and social sciences, provides valuable insights which may to be applicable on several other islands where cats and people are present and in conflict with conservation priorities.

High-impact conservation: invasive mammal eradications from the islands of western Mexico

Aguirre-Muñoz, A., Croll, D. A., Donlan, C. J., Henry III, R. W., Hermosillo, M. A., Howald, G. R., ... & Samaniego-Herrera, A. (2008). High-impact conservation: invasive mammal eradications from the islands of western Mexico. AMBIO: A Journal of the Human Environment, 37(2), 101-107.

Islands harbor a disproportionate amount of the earth's biodiversity, but a significant portion has been lost due in large part to the impacts of invasive mammals. Fortunately, invasive mammals can be routinely removed from islands, providing a powerful tool to prevent extinctions and restore ecosystems. Given that invasive mammals are still present on more than 80% of the world's major islands groups and remain a premier threat to the earth's biodiversity, it is important to disseminate replicable, scaleable models to eradicate invasive mammals from islands. We report on a successful model from western México during the past decade. A collaborative effort between nongovernmental organizations, academic biologists, Mexican government agencies, and local individuals has resulted in major restoration efforts in three island archipelagos. Forty-two populations of invasive mammals have been eradicated from 26 islands. For a cost of USD 21 615 per colony and USD 49 370 per taxon, 201 seabird colonies and 88 endemic terrestrial taxa have been protected, respectively. These conservation successes are a result of an operational model with three main components: i) a tri-national collaboration that integrates research, prioritization, financing, public education, policy work, capacity building, conservation action, monitoring, and evaluation; ii) proactive and dedicated natural resource management agencies; and iii) effective partnerships with academic researchers in México and the United States. What is now needed is a detailed plan to eradicate invasive mammals from the remaining islands in the region that integrates the needed additional financing, capacity, technical advances, and policy issues. Island conservation in western México provides an effective approach that can be readily applied to other archipelagos where conservation efforts have been limited.

Home range of feral cats on Rota Is.

Leo, B. T., Anderson, J. J., Brand Phillips, R., & Ha, R. R. (2016). Home range estimates of feral cats (Felis catus) on Rota Island and determining asymptotic convergence 1. Pacific Science, 70(3), 323-331.

Feral cats (Felis catus) have been shown to be a main contributor to species decline throughout the world and are especially threatening to insular species that lack appropriate defense characteristics. To mitigate the impact of feral cats on threatened species, space-use data are commonly used to design control strategies. In this article we report on the performance of GPS datalogging collars and provide baseline information on daily space use and home ranges of feral cats that threaten an endangered species on Rota Island in the Commonwealth of the Northern Mariana Islands. Using 100% Minimum Convex Polygon (MCP), average adult male home range was 1.32 km²(n = 2) and average adult female home range was 0.22 km²(n = 3). Home ranges were deemed fully revealed if asymptotes were approached using incremental analysis. Currently, there is no objective method for assessing where an asymptote is approached. Here, we describe a methodology to do so with the application of a Michaelis-Menten model to incremental data. We conclude that GPS datalogging collars are a viable tool for feral cat location data collection on Rota Island and that the Michaelis-Menten model is useful for determining asymptotic convergence of incremental location data.

Epidemiological survey of zoonotic helminths in feral cats in Gran Canaria

Rodríguez-Ponce, E., González, J. F., de Felipe, M. C., Hernández, J. N., & Raduan Jaber, J. (2016). Epidemiological survey of zoonotic helminths in feral cats in Gran Canaria island (Macaronesian archipelago-Spain). Acta Parasitologica, 61(3), 443-450.

The presence of zoonotic parasites in feral cats have been widely considered all over the world. In Gran Canaria (Macaronesian archipelago, Canary Islands, Spain) the number of feral cats has grown out of control in urban and rural areas. 48 of Felis catus captured in different Gran Canaria areas were studied. Animals were necropsied and several organs were systematically examined in order to collect and identify macroscopic parasites. In addition, coprological tests were done in 28 cats. There were no statistically significant differences in the prevalence rate among sex, age or capture area, showing an overall prevalence of helminths of 77.1%. The most common tapeworms were Dipylidium caninum (64.6%) and Taenia taeniaeformis (31.3%), followed by the nematodes Toxocara cati (20.8%), Ancylostoma tubaeforme (18.8%), Aelurostrongylus abstrusus (10.4%) and Trichuris vulpis (2.08%). We also find several eggs of Alaria alata in the small intestine of one cat (2.08%), being the first description of this trematode in cats in the Canary Islands. Aproximatelly, 40% of the studied cats harboured more than one parasite. High rates of zoonotic species found in these animals suggest the need of controling parasitic infections and preventive measures against them.

Invasive stray and feral dogs limit endangered fossa populations in Madagascar

Barcala O. 2009. Invasive stray and feral dogs limit fosa (Cryptoprocta ferox) populations
in Ankarafantsika National Park, Madagascar. Duke University (M.Sc. thesis),
Durham, North Carolina, U.S.A. 

The fosa (Cryptoprocta ferox) is a medium sized carnivore of the family Eupleridae which is endemic to the island of Madagascar. Recent publications have shown that the fosa is under significant pressure from deforestation and fragmentation, leading to its classification as Threatened under the Endangered Species Act. A trap study was conducted from 1999 to 2008 in Ankarafantsika National Park, Madagascar, to ascertain the health of a population and measure additional threats to its survival. Feral dogs (Canis lupus familiaris) appeared in the park in 2004 and a comparison of trap rates of the two species shows an inverse relationship between the presence of dogs and the presence of fosa. In this paper I discuss reasons for this relationship, the effect of the continued presence of dogs, and implications for the management of the park.

Feral cats and dogs the most abundant carnivores in endangered Fossa habitat

Mann, G. K. H., & Hawkins, F. 2015. First record of Fossa Cryptoprocta ferox in Mariarano forest, Madagascar. Small Carnivore Conservation 52 & 53: 45–55

We surveyed the carnivore community in two patches of forest around Mariarano village in north-western Madagascar using camera traps. Cameras were set along trails in the forest and were active for a total of 517 trap nights. We recorded the presence of two indigenous carnivore species, Fossa Cryptoprocta ferox and Western Falanouc Eupleres major, and three introduced carnivore species; Small Indian Civet Viverricula indica, domestic dogs Canis familiaris and domestic cats Felis catus. This is the first record of C. ferox in the Mariarano forest area. We discuss the significance of this
finding, as well as a potential extirpation of E. major in the Matsedroy forest patch.

Modelling the population control of the domestic cat from an island

Lessa, I. C. M., & Bergallo, H. G. (2012). Modelling the population control of the domestic cat: an example from an island in Brazil. Brazilian Journal of Biology, 72(3), 445-452.

The domestic cat is an invasive species that often causes great impacts where introduced due to its high predatory and reproductive potential, especially on islands. In this study, carried out on Ilha Grande (RJ, Brazil), we aimed to: i) estimate the population density of domestic cats, ii) calculate the number of animals preyed upon annually by domestic cats, and iii) evaluate the efficiency of methods to control the cat population. We used the Vortex program to project the population growth of domestic cats in fifty years, and simulated different scenarios of population control (without control, castration, spay and harvest). Population density of owned cats was 662 cats/km². The annual predation rate was 1.97 prey animals/cat which is an average of 1497.96 prey/year. The population would only be reduced if 70% of females were spayed or removed annually. Measures to control the domestic cat population must be undertaken urgently, since uncontrolled growth of this predator has the potential to seriously impact the biodiversity of Ilha Grande.

______________________

O gato doméstico é uma espécie invasora que frequentemente causa grandes impactos onde é introduzido, em razão do seu alto potencial predatório e reprodutivo, especialmente em ilhas. Com este estudo realizado na Ilha Grande-RJ, Brasil, tivemos como objetivos: i) estimar a densidade populacional de gatos domésticos; ii) calcular o número de animais predados anualmente por gatos domésticos, e iii) estimar a eficiência de métodos para o controle da população de gatos. Nós utilizamos o programa Vortex para projetar o crescimento da população de gatos em 50 anos e simulamos diferentes cenários de controle populacional: sem controle, castração, esterilização de fêmeas e remoção de indivíduos. A densidade populacional de gatos que possuem donos foi de 662 gatos/km². A taxa anual de predação foi de 1,97 animais predados/gato, ou seja, uma média de 1497,96 presas/ano. A população de gatos pode ser reduzida apenas se no mínimo 70% das fêmeas forem esterilizadas ou removidas anualmente. Medidas para o controle populacional de gatos domésticos devem ser tomadas com urgência, uma vez que o crescimento descontrolado da população desse predador tem o potencial de causar graves impactos à biodiversidade da Ilha Grande.

Removal of feral dogs by befriending them

Morley, C. G. (2006). Removal of feral dogs Canis familiaris by befriending them, Viwa Island, Fiji. Conservation Evidence, 3(3).

On a Fijian island a decision was made to remove feral dogs Canis familiaris as they were predating
upon endangered fauna. Rather than trapping or shooting, by offering food and gradually habituating
them to people, almost all were captured unharmed and moved to the main island of Fiji. 

Toxoplasmosis in sea lions in NZ

Michael, S. A., Howe, L., Chilvers, B. L., Morel, P. C. H., & Roe, W. D. (2016). Seroprevalence of Toxoplasma gondii in mainland and sub-Antarctic New Zealand sea lion (Phocarctos hookeri) populations. New Zealand Veterinary Journal, (just-accepted), 1-14.

AIMS: To investigate the seroprevalence to Toxoplasma gondii in New Zealand sea lions (Phocarctos hookeri), as a potential contributor to reproductive failure.
METHODS: Archived sera were sourced from New Zealand sea lions from two recolonising mainland populations in the Otago Peninsula (n=15) and Stewart Island (n=12), as well as a declining population at Enderby Island (n=28) in the New Zealand sub-Antarctic. Sera were tested for antibodies to T. gondii using a commercially available ELISA (with samples considered positive if the sample to positive ratio was >30%), and latex agglutination test (LAT; with titres ≥1:32 considered positive). Western blot analysis was used to validate the results of a subset of 14 samples.
RESULTS: Five samples from sea lions in mainland locations were confirmed positive for antibodies to T. gondii. Two adult females exhibited high LAT antibody titres (min 1:2048, max 1:4096) on both occasions when sampled 1 and 2 years apart, respectively. No animals from Enderby Island were seropositive.
CONCLUSIONS: Toxoplasma gondii infection is unlikely to be a major contributor to poor reproductive success in New Zealand sea lions. However, continued surveillance is pertinent to assess subclinical and clinical impacts of the parasite on these threatened populations. The commercial tests evaluated here, with further species-specific threshold refinement could provide a fast, inexpensive and reliable indicator of T. gondii exposure in New Zealand sea lions.

Stray dog control and zoonotic disease prevention in Grenada

Marisa, D., Cotran, E. K., Bidaisee, S., & Keku, E. O. (2016). The Effectivenessof Stray Dog Control and Zoonotic Disease Prevention in Global Health: An One Health Approach from Grenada. J Translational Diagn Technol, 1(1), 1-6.

Introduction: CranThe purpose of this study is to evaluate the effectiveness of stray dog control and disease prevention in Grenada by using a one health approach and address the associated global health implications.
Methods: A review of stray dog policy in Grenada, descriptive statistics analysis and interviews were conducted. World Organization for Animal Health’s and Grenada Dogs Registration and Control Act were reviewed. Quantitative data from 2008-2012 on registration, vaccinations, number of dog complaints filed and outcome of dog captures. Retrospective, oneon-one interviews with 14 stakeholders from three groups identified as being directly associated with the stray dog prevention
and control were performed.
Results: The Grenada Dogs Registration and Control Act provided an adequate framework for stray dog control. There was a decrease in the number of dogs registered and vaccinated and a steady increase in dogs captured and related complaints. Interview data suggested that community education, dog ownership, non-governmental organization involvement, and Grenada’s Stray Dog Control Program (SDCP) responsibility are needed to strengthen stray dog control programs and
disease prevention.
Discussion: Expansion of SDCP services is needed to reduce free-roaming dogs and disease risk to humans. A positive response from program users suggested that the SDCP is well-received by the community. Integration among stakeholders and increased access to the program's services in rural communities is needed. These findings have implication for further policy development to reduce global health risks associated with zoonotic diseases found in stray dogs.