Feral Cats Felis Catus Research Articles

Quantifying fine-scale resource selection by introduced feral cats to complement management decision-making in ecologically sensitive areas

The feral domestic cat (Felis catus) is considered to be one of the most damaging introduced predators, responsible for the decline and extinction of numerous native species. Advanced satellite technologies enable the study of resource selection by small mammals at fine-scales through remote data. These tools can improve understanding of the spatial ecology of introduced predators in ecologically sensitive areas, such as where cats pose a threat to native species and where improvement of predator control methods is required. We studied fine-scale resource selection by feral cats in the ecologically important New Zealand braided-river ecosystem, where they pose a risk to endangered native ground-nesting birds. We collected 34 location datasets from 21 cats fitted with lightweight global positioning system-collars, and extracted landscape variables from a resource map created using very high spatial resolution satellite imagery (Quickbird) and object-base imagery analysis for image classification. We modelled second-order seasonal and annual resource selection functions and characterized landscape composition of highly-used areas using compositional analysis. At a population level, cats generally selected fine-scale landscapes that are important for their primary prey rabbits (Oryctolagus cuniculus), and for refugia. An external validation of the annual model using data from cats tracked in an independent study showed a positive correlation with model predictions. Individual cats also visited habitats used by native ground-nesting birds, and thus pose a threat to them through secondary predation or individual specialization. Cat control operations should therefore focus around areas of concentrated ground-nesting bird activity and in areas identified as high-use by cats.

Regional seroprevalence of Toxoplasma gondii antibodies in feral and stray cats (Felis catus) from Tasmania

Toxoplasma gondii is a cosmopolitan protozoan parasite of felids that also has significant implications for the health of wildlife, livestock and humans worldwide. In Australia, feral, stray and domestic cats (Felis catus) are the most important definitive host of T. gondii as they are the only species that can excrete the environmentally resistant oocysts that provide a major source of infection for mammals and birds. In Tasmania, the rapid decline of the Tasmanian devil (Sarcophilus harrisii) may allow an increase in feral cat abundance, thereby increasing the risk of T. gondii infection to a range of susceptible wildlife species. At present, there is scant information on the prevalence of T. gondii infection in feral cat populations across Tasmania. We tested feral cats from 13 regions across Tasmania for the presence of T. gondii–specific IgG antibodies using a modified agglutination test. Results were combined with serosurveys from three previous studies to enable a comparison of seroprevalence among 14 regions across Tasmania. We found that 84.2% (224 of 266) of cats tested positive for T. gondii IgG antibodies. This is among the highest rates of prevalence recorded from Australia, and significantly higher than for most other countries. Adult cats had higher seroprevalence than kittens but there was no difference between sexes. In Tasmania, seroprevalence was high in 12 of 14 regions (range: 79.3–100.0%), with only two regions (Tasman Island and Southern Tasmania) recording significantly lower seroprevalence (≤50%). This suggests a high risk of infection across Tasmania, and has significant implications for wildlife conservation should feral cat abundance increase with the ongoing declines in Tasmanian devils.

Feline patent Toxoplasma-like coccidiosis among feral cats (Felis catus) in Doha city, Qatar and its immediate surroundings.

Doha city has a high feral cat population and studies of hospital records in Doha have shown that human toxoplasmosis also occurs. Clearly, there is a need to understand the role of cats as vectors of human toxoplasmosis in the city and as a first step we assessed the extent of patent Toxoplasma-like coccidial infections among feral cats. Oocysts in cat faeces were detected between June 2008 and April 2010, from a range of locations radiating out of the city centre in concentric semi circular/elliptic rings and by north, west and south divisions within each of the rings. In total 4,652 cats were sampled and overall prevalence of oocysts was 9.1%. Prevalence was 10.1% in the first summer, and then dropped to 8.4% in the following winter and further to 6.8% in the next summer before rising to 10.6% in the final winter of the study; this interaction between annual period and season was significant. There were also significant changes in prevalence across each of the consecutive months of the study, but no clear pattern was evident. Prevalence did not vary significantly by city sector and there was no difference in prevalence between the host sexes. We conclude therefore, that despite minor and significant perturbations, the prevalence of patent Toxoplasma-like coccidial infections among cats in Doha is remarkably stable throughout the year, across years and spatially within the city's districts.

Rapid decline in detections of the Tasmanian bettong (Bettongia gaimardi) following local incursion of feral cats (Felis catus)

An abrupt decline in the number of Tasmanian bettongs (Bettongia gaimardi) was observed as part of a study investigating population declines in the eastern quoll (Dasyurus viverrinus). Seven remote camera surveys were undertaken at a monitoring site between February 2012 and October 2013. An 11% reduction in bettong detections was observed immediately following the first appearance of feral cats (Felis catus) (at least three individuals) at the site. Within four months, bettong detections had fallen by 58% and by 100% within six months. No bettongs were detected in subsequent surveys undertaken 10, 12 and 16 months after cats were first observed. Cat predation and toxoplasmosis are discussed as mechanisms possibly responsible for the local disappearance of bettongs from this site, together with implications for the future management and conservation of the species.

A critical review of habitat use by feral cats and key directions for future research and management

Feral cats (Felis catus) have a wide global distribution and cause significant damage to native fauna. Reducing their impacts requires an understanding of how they use habitat and which parts of the landscape should be the focus of management. We reviewed 27 experimental and observational studies conducted around the world over the last 35 years that aimed to examine habitat use by feral and unowned cats. Our aims were to: (1) summarise the current body of literature on habitat use by feral and unowned cats in the context of applicable ecological theory (i.e. habitat selection, foraging theory); (2) develop testable hypotheses to help fill important knowledge gaps in the current body of knowledge on this topic; and (3) build a conceptual framework that will guide the activities of researchers and managers in reducing feral cat impacts. We found that feral cats exploit a diverse range of habitats including arid deserts, shrublands and grasslands, fragmented agricultural landscapes, urban areas, glacial valleys, equatorial to sub-Antarctic islands and a range of forest and woodland types. Factors invoked to explain habitat use by cats included prey availability, predation/competition, shelter availability and human resource subsidies, but the strength of evidence used to support these assertions was low, with most studies being observational or correlative. We therefore provide a list of key directions that will assist conservation managers and researchers in better understanding and ameliorating the impact of feral cats at a scale appropriate for useful management and research. Future studies will benefit from employing an experimental approach and collecting data on the relative abundance and activity of prey and other predators. This might include landscape-scale experiments where the densities of predators, prey or competitors are manipulated and then the response in cat habitat use is measured. Effective management of feral cat populations could target high-use areas, such as linear features and structurally complex habitat. Since our review shows often-divergent outcomes in the use of the same habitat components and vegetation types worldwide, local knowledge and active monitoring of management actions is essential when deciding on control programs.

Laysan Albatross on Guadalupe Island, México: Current Status and Conservation Actions

Guadalupe Island, off the Baja California peninsula, México, hosts the most important growing Laysan Albatross (Phoebastria immutabilis) breeding colony in the eastern Pacific. Since this seabird's first arrival in 1983, it has been affected by predation from feral cats (Felis catus), present on Guadalupe since the late 19th century. Heavy predation events have been recorded on the island, so we initiated a feral cat control campaign in 2003 and began collecting baseline information for developing an eradication plan. At the same time, we conducted seasonal monitoring of Laysan Albatross reproductive success in order to assess the benefits from control activities. Cat relative abundance on Guadalupe was estimated through spotlight surveys, and control was done at the southernmost end of the island around the 2 locations where Laysan Albatross nest: Colinas Negras and Punta Sur. Laysan Albatross population growth rate was calculated based on the number of reproductive individuals, while breeding success was estimated as the proportion of laid eggs that resulted in fledged chicks. A total of 203 cats were removed from the south end of Guadalupe between 2003 and 2013. During this same period, high reproductive success (0.8) was recorded for Laysan Albatross, suggesting a positive effect of cat control activities. We found significant differences in reproductive success between years with predation and no predation by feral cats. The Laysan Albatross colony on Guadalupe has grown steadily during the past 30 years, increasing from 4 to 143 breeding pairs between 1984 and 2013, respectively, and with a population growth rate of 1.10 between 2004 and 2013.

Eradication of cats (Felis catus) from subantarctic Macquarie Island

SummaryThe feral Cat (Felis catus) population on Macquarie Island was targeted for eradication between 1996 and 2002, with 761 cats captured during this period. After 22 years of cat control from 1974 integrated with control programmes for other pests, effort intensified for 2 years before a dedicated eradication programme began in 1998. The primary knock‐down for the eradication used cage trapping and shooting, with most surviving cats captured with leg‐hold traps. A total of 6298 field days and 216 574 trap nights were recorded in this operation. Factors contributing to the success of the programme included extensive planning, increased staff numbers at critical times, better access to remote areas of the island, introduction of leg‐hold traps, sufficient operational funding and good collaboration between government agencies operating on the island. The programme would have benefited from earlier deployment of detector dogs and better posteradication monitoring of a broader range of native species impacted by cats. The successful eradication of cats from Macquarie Island, being the second largest achieved to date, provides valuable experience for cat eradication attempts on other large remote islands. This programme relied on ground‐based techniques with minimal use of poisons and provides possible options for sites where broad‐scale poisoning, or where aerial distribution of poisons, cannot be used.

Trophic Cascades Following the Disease‐Induced Decline of an Apex Predator, the Tasmanian Devil

As apex predators disappear worldwide, there is escalating evidence of their importance in maintaining the integrity and diversity of the ecosystems they inhabit. The largest extant marsupial carnivore, the Tasmanian devil (Sarcophilus harrisii) is threatened with extinction from a transmissible cancer, devil facial tumor disease (DFTD). The disease, first observed in 1996, has led to apparent population declines in excess of 95% in some areas and has spread to more than 80% of their range. We analyzed a long-term Tasmania-wide data set derived from wildlife spotlighting surveys to assess the effects of DFTD-induced devil decline on populations of other mammals and to examine the relative strength of top-down and bottom-up control of mesopredators between 2 regions with different environmental conditions. Collection of the data began >10 years before DFTD was first observed. A decrease in devil populations was immediate across diseased regions following DFTD arrival, and there has been no indication of population recovery. Feral cats (Felis catus) increased in areas where the disease was present the longest, and feral cat occurrence was significantly and negatively associated with devils. The smallest mesopredator, the eastern quoll (Dasyurus viverrinus), declined rapidly following DFTD arrival. This result suggests the species was indirectly protected by devils through the suppression of larger predators. Rainfall deficiency was also a significant predictor of their decline. Environmental variables determined the relative importance of top-down control in the population regulation of mesopredators. In landscapes of low rainfall and relatively higher proportions of agriculture and human settlement, top-down forces were dampened and bottom-up forces had the most effect on mesopredators. For herbivore prey species, there was evidence of population differences after DFTD arrival, but undetected environmental factors had greater effects. The unique opportunity to assess population changes over extensive temporal and spatial scales following apex predator loss further demonstrated their role in structuring ecosystems and of productivity in determining the strength of top-down control.

Modelling Landscape-Level Numerical Responses of Predators to Prey: The Case of Cats and Rabbits

Predator-prey systems can extend over large geographical areas but empirical modelling of predator-prey dynamics has been largely limited to localised scales. This is due partly to difficulties in estimating predator and prey abundances over large areas. Collection of data at suitably large scales has been a major problem in previous studies of European rabbits (Oryctolagus cuniculus) and their predators. This applies in Western Europe, where conserving rabbits and predators such as Iberian lynx (Lynx pardinus) is important, and in other parts of the world where rabbits are an invasive species supporting populations of introduced, and sometimes native, predators. In pastoral regions of New Zealand, rabbits are the primary prey of feral cats (Felis catus) that threaten native fauna. We estimate the seasonal numerical response of cats to fluctuations in rabbit numbers in grassland–shrubland habitat across the Otago and Mackenzie regions of the South Island of New Zealand. We use spotlight counts over 1645 km of transects to estimate rabbit and cat abundances with a novel modelling approach that accounts simultaneously for environmental stochasticity, density dependence and varying detection probability. Our model suggests that cat abundance is related consistently to rabbit abundance in spring and summer, possibly through increased rabbit numbers improving the fecundity and juvenile survival of cats. Maintaining rabbits at low abundance should therefore suppress cat numbers, relieving predation pressure on native prey. Our approach provided estimates of the abundance of cats and rabbits over a large geographical area. This was made possible by repeated sampling within each season, which allows estimation of detection probabilities. A similar approach could be applied to predator-prey systems elsewhere, and could be adapted to any method of direct observation in which there is no double-counting of individuals. Reliable estimates of numerical responses are essential for managing both invasive and threatened predators and prey.

Analysis of the Summer Season Home Range of Domestic Feral Cats (Felis catus) - Focused on the Surroundings of Rural and Suburban Areas

In order to analyze the home range of feral cats residing in the surroundings of rural and suburban areas, we collected coordination information data from five feral cats. As a result of such research, 100% MCP was defined as minimum 31,500 and maximum 351,900, and 95% KR was defined as minimum 9,400 and maximum 502,800, 75% KR was defined as minimum 3,600 and maximum 126,900, and 50% MCP was defined as minimum 1,800 and maximum 51,700. The home range of feral cats was also analyzed during daytime and nighttime, and all five individuals showed a wider home range during the nighttime than daytime. The analysis of gender shows that the average home range of female feral cats is larger than the average of males. Meanwhile, the results of information data with wide-open areas such as farm land and terrace land on the river showed that the analyzed value was increased generally, and showed variable values depending on the gender and size of each individual feral cat.

Landscape resource mapping for wildlife research using very high resolution satellite imagery

Summary Quantifying wildlife‐habitat relationships through resource selection analysis (RSA) has traditionally relied on landscape variables extracted at medium‐to‐coarse scales and general‐purpose digital maps. However, RSA at fine scales, facilitated by accurate positional data obtained using GPS‐tags, requires improved measures of habitat resources. The combination of cutting‐edge remote sensing technology, such as very high spatial resolution (VHSR) satellite imagery and object‐based image analysis (OBIA), can provide landscape maps that are suitable for the extraction of detailed variables at fine scale. We used Quickbird satellite imagery and OBIA to produce a map using the multispectral bands (MULT), and explored the usefulness of the technique for resource identification by combining the panchromatic (highest spatial resolution) and multispectral (spectral information) bands (PAN:MULT) to produce a second map. Each of the mapping methods was used in a heterogeneous braided‐river environment in New Zealand to: (1) classify and delimit ground features using an object‐based accuracy assessment approach; (2) detect ground features of different sizes; (3) extract independent landscape variables at fine scale (within buffers between 20 and 30 m) for separate RSA for introduced hedgehogs (Erinaceus europaeus) and feral cats (Felis catus). Per‐pixel accuracy assessment produced overall accuracies of 82% (PAN:MULT) and 79% (MULT). The per‐object assessment using shrubs as the testing class yielded further information on classification and delimitation of object accuracy, with accuracies of 80% for shrub patches ≥30 m2 in MULT and ≥5 m2 in PAN:MULT. The inclusion of the panchromatic band noticeably improved the identification and delimitation of cover. However, RSA using each of the maps did not yield differences in the best models for cats or hedgehogs. VHSR imagery and OBIA provide a valuable method to identify smaller ground features and thus to produce more detailed landscape maps to study animal habitat use at fine scale. Improvements in ground feature detection achieved by including the panchromatic band may not justify its cost, as it was shown for the studies on cats and hedgehogs presented here. However, the level of detail offered by the panchromatic layer may be useful for addressing other RSA questions or applications at fine scale, such as remote censusing of colonial species.

Understanding determinants of home range behaviour of feral cats as introduced apex predators in insular ecosystems: a spatial approach

The introduced feral cat (Felis catus) is a widespread generalist with flexible social behaviour and an apex predator without major interspecific competitors in insular ecosystems that evolved in the absence of predators. Mechanistic definitions consider an animal’s home range to be the spatial expression of a cognitive map that is kept up-to-date with the status of critical resources that contribute to animal fitness. We assumed there are two major determinants structuring the home range of cats as apex predators in insular ecosystems: the distribution of critical food resources and conspecific distribution. We hypothesized that cats structure their home ranges by optimizing the use of staple critical food resources and that as a consequence of the presence of rich resources cats tend to socialise, aggregate and share space. We carried out spatial analyses using location data for feral cats tracked using lightweight GPS collars in conjunction with the suitability value of rabbit patches and their associated ownership costs for cats within a New Zealand braided-river environment. Cat home ranges and spatial distribution, especially for females, were related to the inclusion of rabbit patches within home ranges with higher mean value than the average of neighbourhood patches in the landscape. Cats showed solitary behaviour but tolerance to conspecific presence by sharing high-use areas and high-value rabbit patches, mostly at different times, resulting in occasional encounters among males and females. Home range size and patterns of spatial overlap were dependant on sex and season. Solitary spacing patterns as consequence of innate preferences together with resource constraints may regulate feral cat population densities.

BartonellaSpecies in Raccoons and Feral Cats, Georgia, USA

<i>Bartonella</i>Species in Raccoons and Feral Cats, Georgia, USA

Optimising Camera Traps for Monitoring Small Mammals

Practical techniques are required to monitor invasive animals, which are often cryptic and occur at low density. Camera traps have potential for this purpose, but may have problems detecting and identifying small species. A further challenge is how to standardise the size of each camera’s field of view so capture rates are comparable between different places and times. We investigated the optimal specifications for a low-cost camera trap for small mammals. The factors tested were 1) trigger speed, 2) passive infrared vs. microwave sensor, 3) white vs. infrared flash, and 4) still photographs vs. video. We also tested a new approach to standardise each camera’s field of view. We compared the success rates of four camera trap designs in detecting and taking recognisable photographs of captive stoats ( Mustela erminea ), feral cats (Felis catus) and hedgehogs ( Erinaceus europaeus ). Trigger speeds of 0.2–2.1 s captured photographs of all three target species unless the animal was running at high speed. The camera with a microwave sensor was prone to false triggers, and often failed to trigger when an animal moved in front of it. A white flash produced photographs that were more readily identified to species than those obtained under infrared light. However, a white flash may be more likely to frighten target animals, potentially affecting detection probabilities. Video footage achieved similar success rates to still cameras but required more processing time and computer memory. Placing two camera traps side by side achieved a higher success rate than using a single camera. Camera traps show considerable promise for monitoring invasive mammal control operations. Further research should address how best to standardise the size of each camera’s field of view, maximise the probability that an animal encountering a camera trap will be detected, and eliminate visible or audible cues emitted by camera traps.

Experimental Transmission ofSarcocystis muris(Apicomplexa: Sarcocystidae) Sporocysts from a Naturally Infected Cat (Felis catus) to Immunocompetent and Immunocompromised Mice

Cats serve as definitive hosts for zoonotic Toxoplasma gondii , a protozoan that threatens human reproductive health, but they also excrete sporocysts of related protozoan that pose no known human health risk. Here we provide the first definitive evidence for natural infection with the enzootic parasite Sarcocystis muris, one such enzootic parasite. Sporulated Sarcocystis sp. sporocysts were found in rectal contents of an adult feral cat ( Felis catus ) in Giza, Egypt. After these sporocysts were orally inoculated into 2 Swiss Webster mice, sarcocysts were found to have developed in skeletal muscles 114 days later. As observed through transmission electron microscopy, the cyst wall corresponded to Type 1, and the parasitophorous vacuolar membrane had tiny outpocketing of blebs (<200 nm thick) that were not invaginated into the interior of the cyst; these structures were identical to the sarcocyst wall described for a Costa Rican isolate of S. muris that has served as an experimental model for nearly 4 decades. Two parasite-free cats fed sarcocyst-infected muscles developed patent infections; fully sporulated sporocysts (10-11 × 7.0 μm) were found in the lamina propria of small intestines of cats killed 6 and 7 days postinoculation (PI). Interferon gamma gene knockout (KO) mice were orally inoculated with sporocysts from experimentally infected cats, and their tissues were examined histologically; sarcocysts were found in 5 KO mice killed 87, 115, 196, 196, 196 days PI, but no stages were seen in 5 KO mice 10, 14, 14, 18, and 39 days PI. Bradyzoites were released from intramuscular sarcocysts of a KO mouse killed 115 days PI and orally inoculated into 5 KO mice. No stage of Sarcocystis was found in any organ (including intestinal lamina propria) of KO mice killed 4, 8, 81, 190, and 190 days PI, confirming that the definitive host is required to complete the life cycle even in the case of immunodeficient mice. This is the first confirmation of S. muris infection in a naturally infected cat anywhere.

The current decline of tropical marsupials inAustralia: is history repeating?

AbstractAimA third of all modern (after 1500) mammal extinctions (24/77) are Australian species. These extinctions have been restricted to southernAustralia, predominantly in species of ‘critical weight range’ (35–5500 g) in drier climate zones. Introduced red foxes (Vulpes vulpes) that prey on species in this range are often blamed. A new wave of declines is now affecting a globally significant proportion of marsupial species (19 species) in the fox‐free northern tropics. We aim to test plausible causes of recent declines in range and determine if mechanisms differ between current tropical declines and past declines, which were in southern (non‐tropical) regions.LocationAustralian continentMethodsWe used multiple regression and random forest models to analyse traits that were associated with declines in species range, and compare variables associated with past extinctions in the southern zones with current tropical (northern) declines.ResultsThe same two key variables, body mass and habitat structure, were associated with proportion‐of‐decline in range throughout the continent, but the form of relationships differs with latitude. In the south, medium‐sized species in open habitats of lower rainfall were most likely to decline. In the tropics, small species that occupy open vegetation with moderate rainfall (savanna) are now experiencing the most severe declines. Throughout the continent, large‐bodied species and those in structurally complex habitats (rainforest) are secure.Main conclusionsOur results indicate that there is no mid‐sized ‘critical weight range’ in the north. Because foxes are absent from the tropics, we suggest that northern Australian marsupial declines are associated with predation by feral cats (Felis catus) exacerbated by reduced ground level vegetation in non‐rainforest habitats. To test this, we recommend experiments to remove cats from some locations where tropical mammals are threatened. Our results show that comparative analysis can help to diagnose potential causes of multi‐species decline.

Are declines of an endangered mammal predation‐driven, and can a captive‐breeding and release program aid their recovery?

AbstractDeclines of imperiled small mammals are often attributed to predation without investigating the relative influence of survival and reproductive parameters on population growth. Accordingly, declines in the endangered Key Largo woodrat Neotoma floridana smalli (KLWR) population have been attributed to predation by feral cats Felis catus, Burmese pythons Python molurus bivittatus and raccoons Procyon lotor. We estimated survival, recruitment and realized population growth rates from four capture–mark–recapture studies to determine if the pattern of demographic variation was consistent with predation as the primary cause of KLWR declines. Additionally, we evaluated the KLWR captive‐breeding and release program by comparing survival of captive‐born and released KLWRs to wild‐born KLWRs. The realized population growth rate of wild‐born KLWRs had a strong pattern of covariation with recruitment; covariation between the realized population growth rate and apparent survival was negligible. Consistent with demographic theory, our results suggest that KLWR population dynamics were driven primarily by variation in recruitment, and that periodic reductions in recruitment led to population declines. We found that the survival curve and the first month (S1) and first 3‐month (S1–3) survival estimates for the wild‐born KLWRs [S1 = 0.929 (0.890–0.968); S1–3 = 0.942 (0.919–0.965)] were considerably higher (χ2 = 33.9, 1 d.f., P &lt; 0.001) than released KLWRs [S1 = 0.521 (0.442–0.600); S1–3 = 0.561 (0.493–0.629)]. Low survival rates from predation limited the success of the captive‐breeding and release program. This study illustrates the importance of pre‐release conditioning of captive‐bred animals and the importance of considering reproductive parameters in conjunction with survival estimates to understand the drivers of population decline.

Patterns of detection and capture are associated with cohabiting predators and prey.

Avoidance behaviour can play an important role in structuring ecosystems but can be difficult to uncover and quantify. Remote cameras have great but as yet unrealized potential to uncover patterns arising from predatory, competitive or other interactions that structure animal communities by detecting species that are active at the same sites and recording their behaviours and times of activity. Here, we use multi-season, two-species occupancy models to test for evidence of interactions between introduced (feral cat Felis catus) and native predator (Tasmanian devil Sarcophilus harrisii) and predator and small mammal (swamp rat Rattus lutreolus velutinus) combinations at baited camera sites in the cool temperate forests of southern Tasmania. In addition, we investigate the capture rates of swamp rats in traps scented with feral cat and devil faecal odours. We observed that one species could reduce the probability of detecting another at a camera site. In particular, feral cats were detected less frequently at camera sites occupied by devils, whereas patterns of swamp rat detection associated with devils or feral cats varied with study site. Captures of swamp rats were not associated with odours on traps, although fewer captures tended to occur in traps scented with the faecal odour of feral cats. The observation that a native carnivorous marsupial, the Tasmanian devil, can suppress the detectability of an introduced eutherian predator, the feral cat, is consistent with a dominant predator – mesopredator relationship. Such a relationship has important implications for the interaction between feral cats and the lower trophic guilds that form their prey, especially if cat activity increases in places where devil populations are declining. More generally, population estimates derived from devices such as remote cameras need to acknowledge the potential for one species to change the detectability of another, and incorporate this in assessments of numbers and survival.

Molecular and Biological Characterization of First Isolates ofHammondia hammondifrom Cats from Ethiopia

Toxoplasma gondii oocysts are morphologically and antigenically similar to oocysts of another feline coccidian, Hammondia hammondi. The distinction between H. hammondi and T. gondii is important from an epidemiological perspective because all isolates of T. gondii are potentially pathogenic for humans and animals, whereas H. hammondi is not known to cause clinical disease in any naturally infected intermediate or definitive hosts. In the present report, H. hammondi (designated HhCatEt1 and HhCatEt2) oocysts were found microscopically in the feces of 2 of 36 feral domestic cats (Felis catus) from Addis Ababa, Ethiopia. Oocysts were orally infective to Swiss Webster and gamma interferon gene knockout mice; the inoculated mice developed tissue cysts in their muscles. Laboratory-raised cats fed mouse tissues of infected mice shed H. hammondi oocysts with a prepatent period of 5 days. The DNA extracted from sporulated oocysts reacted with H. hammondi-specific primers, and sequences were deposited in GenBank (accession nos. JX477424, and KC223619). This is the first report of isolation of H. hammondi from cats from the African continent.

Evaluating and predicting risk to a large reptile (Varanus varius) from feral cat baiting protocols

Control of introduced predators to mitigate biodiversity impacts is a pressing conservation challenge. Across Australia feral cats (Felis catus) are a major threat to terrestrial biodiversity. Currently feral cat control is hindered by the limited utility of existing predator baiting methods. Further proposed control methods include use of the novel poison para-aminopropiophenone (PAPP) which may present a hazard to some native animal populations. Here we used experimental and predictive approaches to evaluate feral cat bait take by a large native Australian predatory reptile the Lace monitor (Varanus varius). These lizards would be expected to readily detect, ingest and consume a lethal dose (depending on toxin) from surface-laid baits intended for feral cat control if a precautionary approach was not adopted when baiting. We modelled V. varius bait take using experimental and predictive biophysical modelling approaches to evaluate temporal effects of climate variables on V. varius activity and hence potential for bait removal. Finally we conducted a pre-PAPP baiting site occupancy assessment of V. varius within Wilson Promontory National Park (WPNP) to provide a basis for monitoring any longer term population effects of cat baiting. V. varius removed 7 % of deployed baits from 73 % of bait stations across another study area in Far Eastern Victoria. Daily bait removal was positively correlated with maximum temperature and solar radiation. Biophysical modelling for Far Eastern Victoria predicted that maximum temperatures <19.5 °C prevented V. varius activity and hence opportunity for bait removal. V. varius in WPNP was undetectable suggesting aerial baiting posed limited hazard to this species at this location. Depending how climate influences annual activity patterns and the specific poison, surface-laid baits could pose a significant mortality risk to V. varius. However, use of biophysical models to predict periods of V. varius inactivity may provide a novel means to reduce non-target bait take by this predator.