Eradication Of Feral Cats Research Articles

Man versus machine: cost and carbon emission savings of 4G-connected Artificial Intelligence technology for classifying species in camera trap images

Timely and accurate detection and identification of species are crucial for monitoring wildlife for conservation and management. Technological advances, including connectivity of camera traps to mobile phone networks and artificial intelligence (AI) algorithms for automated species identification, can potentially improve the timeliness and accuracy of species detection and identification. Adoption of this new technology, however, is often seen as cost-prohibitive as it has been difficult to calculate the cost savings or qualitative benefits over the life of the program. We developed a decision tool to quantify potential cost savings associated with incorporating the use of mobile phone network connectivity and AI technologies into monitoring programs. Using a feral cat eradication program as a case study, we used our decision tool to quantify technology-related savings in costs and carbon emissions, and compared the accuracy of AI species identification to that of experienced human observers. Over the life of the program, AI technology yielded cost savings of $0.27 M and when coupled with mobile phone network connectivity, AI saved $2.15 M and 115,838 kg in carbon emissions, with AI algorithms outperforming human observers in both speed and accuracy. Our case study demonstrates how advanced technologies can improve accuracy and cost-effectiveness and improve monitoring program efficiencies.

Monitoring and detection of feral cats on Auckland Island

In order to conserve important biodiversity values, eradication of feral cats (Felis catus) is planned on Auckland Island in the New Zealand subantarctic region. This eradication will require detailed knowledge of the abundance, distribution, movement behaviour and detection probability of cats on the island. We investigated these parameters on a peninsula at the northern end of the island using live trapping, camera trapping, and scat searches with and without detection dogs. Here, we compare the results of these methods, and discuss their utility for the planned eradication.

Spatial ecology meets eradication of feral cats on Auckland Island

Restoration initiatives of ecosystems transformed by human actions require optimisation of eradication measures of introduced species, particularly in fragile insular ecosystems. We studied aspects of the spatial ecology of introduced feral cats (Felis catus) on subantarctic Auckland Island of New Zealand to assist eradication efforts of pests from this remote, biologically rich island. Firstly, we estimated home range sizes and identified core areas of activity based on movement-rooted dynamic Brownian bridge models.

Spatial ecology meets eradication of feral cats on Auckland Island

Spatial ecology meets eradication of feral cats on Auckland Island

Characterization of an extinct seabird colony on the island of Santa Luzia (Cabo Verde) and its potential for future recolonizations

Islands worldwide have suffered seabird extinctions after the arrival of humans and the alien species they introduced. On Santa Luzia (Cabo Verde), an uninhabited island of 35 km2, the presence of an impressive quantity of petrel bones in coastal dunes suggested the previous existence of an important seabird colony. Yet, these remains had not been identified and no seabird extinctions have been reported for the island. This paper characterizes the extinct seabird colony of Santa Luzia and discusses the chronology and possible causes of its demise. A total of 130 grid points in a 5 km2 area and 38 supplementary points within and outside the main study area were excavated to collect bone remains. A total of 1318 anatomical elements, identified as White-faced Storm Petrel Pelagodroma marina eadesorum (85.3% of the minimum number of individuals, MNI), Boyd’s Shearwater Puffinus lherminieri boydi (11.8% MNI) and Cape Verde Storm Petrel Hydrobates jabejabe (2.9% MNI), were found in 18% of the sampling points, within 1.25 km2. Neither of the two former species currently breeds on Santa Luzia. In addition, two bones of the Cape Verde Shearwater Calonectris edwardsii and Pterodroma sp. were detected in the supplementary points. Radiocarbon dating of White-faced Storm Petrel (n = 10) and Boyd’s Shearwater bones (n = 13) suggests that the colony probably went extinct during the first half of the twentieth century. The recent extinction of these species on Santa Luzia might be consequent on the arrival of humans and their domestic animals on the island. We estimate that the extinct seabird populations must have been at least hundreds of thousand strong, far larger than current populations of the same species in Cabo Verde. We suggest that, following feral cat eradication, Santa Luzia has a significant potential for seabird restoration.

Pre-eradication assessment of feral cat density and population size across Kangaroo Island, South Australia

Abstract Context Feral cats (Felis catus) are a significant threat to wildlife in Australia and globally. In Australia, densities of feral cats vary across the continent and also between the mainland and offshore islands. Densities on small islands may be at least an order of magnitude higher than those in adjacent mainland areas. To provide cat-free havens for biodiversity, cat-control and eradication programs are increasingly occurring on Australian offshore islands. However, planning such eradications is difficult, particularly on large islands where cat densities could vary considerably. Aims In the present study, we examined how feral cat densities vary among three habitats on Kangaroo Island, a large Australian offshore island for which feral cat eradication is planned. Methods Densities were compared among the following three broad habitat types: forest, forest–farmland boundaries and farmland. To detect cats, three remote-camera arrays were deployed in each habitat type, and density around each array was calculated using a spatially explicit capture–recapture framework. Key results The average feral cat density on Kangaroo Island (0.37 cats km−2) was slightly higher than that on the Australian mainland. Densities varied from 0.06 to 3.27 cats km−2 and were inconsistent within broad habitat types. Densities were highest on farms that had a high availability of macropod and sheep carcasses. The relationship between cat density and the proportion of cleared land in the surrounding area was weak. The total feral cat population of Kangaroo Island was estimated at 1629±661 (mean±s.e.) individuals. Conclusions Cat densities on Kangaroo Island are highly variable and may be locally affected by factors such as prey and carrion availability. Implications For cat eradication to be successful, resources must be sufficient to control at least the average cat density (0.37 cats km−2), with additional effort around areas of high carcass availability (where cats are likely to be at a higher density) potentially also being required.

Uptake of ‘Eradicat’ feral cat baits by non-target species on Kangaroo Island

Abstract ContextPredation by feral cats (Felis catus) threatens a range of vertebrate species across Australia, and cat-free islands increasingly act as safe havens for biodiversity. A feral cat eradication program has begun on Kangaroo Island (4405km2) in South Australia, and poison baiting is likely to be one of the main methods used. Aims Here, we trial a non-toxic version of a cat bait, ‘Eradicat’, on western Kangaroo Island, to examine its potential impact on non-target species. MethodsNon-toxic baits containing the biomarker Rhodamine B were deployed across four sites in early August and late November in 2018, with bait take and consumption assessed both by remote cameras and by the presence of Rhodamine B in mammalian whisker samples taken post-baiting. Key resultsCats encountered baits on very few occasions and took a bait on only one occasion in August (<1% of 576 baits deployed). Non-target species accounted for over 99% of identifiable bait takes. In both seasons, >60% of all baits laid was taken by either the common brushtail possum (Trichosurus vulpecula), bush rat (Rattus fuscipes) or Australian raven (Corvus coronoides). In November, Rosenberg’s goanna (Varanus rosenbergi) and southern brown bandicoot (south-eastern subspecies; Isoodon obesulus obesulus), listed nationally as Endangered, also took baits (3% and 1% respectively). The Kangaroo Island dunnart (Sminthopsis fuliginosus aitkeni), listed nationally as endangered, approached a bait on only one occasion, but did not consume it. Evidence of bait consumption was visible in the whiskers of captured common brushtail possums (100% of post-baiting captured individuals in August, 80% in November), bush rats (59% in August and 50% in November), house mice (Mus musculus) (45% in November) and western pygmy-possums (Cercartetus concinnus) (33% in November). ConclusionsAlthough feral cat baiting has the potential to significantly benefit wildlife on Kangaroo Island, impacts on non-target species (particularly the bush rat and common brushtail possum) may be high. ImplicationsAlternative cat baits, such as those containing a toxin to which native species have a higher tolerance or that are less readily consumed by native wildlife, will be more appropriate.

RECORDS OF Sauromalus ater (DUMÉRIL, 1856) HATCHLINGS AND SUBADULTS ON SAN FRANCISCO ISLAND, GULF OF CALIFORNIA, MÉXICO

Six hatchlings of the Common or Sonoran Desert Chuckwalla (Sauromalus ater) ranging from 60 mm to 93 mm (SVL) as well as 10 subadult individuals (mostly ♀) ranging from 110 mm to 146 mm (SVL) were recorded during three casual walks on the small island San Francisco, Baja California Sur, Gulf of California, México, in January and February, 2019. The presence of these hatchlings and subadult females could be an important sign of chuckwallas’ recovery and of continued population’s recruitment following eradication of feral cats and goats from the island in 1999 and 2000 respectively, and despite the intense presence of humans (fishermen and tourists) on the island. The chuckwalla population seems to be growing and becoming conspicuous on San Francisco after almost two decades of rare and infrequent records of individuals. Also, the vegetation shows more abundance and diversity, and more extensive covering than in previous years. Other vertebrate species, like the Baja California Rattlesnake (Crotalus enyo) and the Burrowing Owl (Athene cunicularia) were recorded as well during the walks. All these observations possibly indicate a whole and progressive biota restoration on this tiny island after devastation by invasive fauna, combined with previous good wet years.

Feral cat eradication on Dirk Hartog Island, Western Australia

Feral cats are known to drive numerous extinctions of endemic species on islands. Predation by feral cats also currently threatens many species listed as critically endangered. Island faunas that have evolved in the absence of mammalian predators are particularly susceptible to cat predation. Dirk Hartog Island is no exception as cats have caused the local extinction of its once high vertebrate diversity. A programme to reconstruct the native fauna on the island necessitated feral cat eradication. In this paper we outline the strategy, removal techniques and monitoring methods used in this successful eradication of feral cats. Globally, the Dirk Hartog project has become the largest successful island feral cat eradication campaign attempted to date.

Estimating feral cat (Felis catus) density in a rural to urban gradient using camera trapping

ABSTRACTControl or eradication of feral cats (Felis cattus) is necessary for a number of reasons, including controlling zoonotic diseases and protecting native species in New Zealand. Estimating feral cat density provides vital information about location and logistical effort required for control operations but current methods used to estimate feral cat densities are often labour intensive and invasive, and may not provide appropriate baseline data. We determined the effectiveness of using camera traps to estimate a feral cat population compared with live-capture trapping in a semi-rural park. Camera trapping, with capture–recapture statistical modelling, was used to estimate population density of feral cats as between 1.06 and 1.19 cats/km2 with an individual detection probability of 5.3% per camera/night. Camera trapping (seven individual feral cats identified) was a valuable addition to live trapping of feral cats (four cats live trapped) and provided a cost-effective, non-invasive and potentially more accurate tool for wildlife managers and researchers to measure feral cat densities.

Feral cat eradication in the presence of endemic San Nicolas Island foxes

Projects to eradicate invasive species from islands are a high priority for conservation. Here we describe the process used to successfully eradicate an introduced carnivore on an island where a native carnivore of similar size was also present. We primarily used padded leg-hold live trapping to capture feral cats (Felis silvestris catus). Trapped feral cats were transported off-island and housed in a permanent enclosure on the continent. We used additional methods, such as tracking dogs and spotlight hunting, to detect and remove more-difficult individuals. Project implementation caused no significant negative impacts to the endemic San Nicolas Island fox (Urocyon littoralis dickey) population. Mitigation measures included on-site veterinary resources, modified padded leg-hold live traps, conditioned trap aversion, a trap monitoring system and personnel training. To confirm eradication, we utilized camera traps and sign search data in a model to predict project success. A key part of the success of this project was the partnerships formed between NGOs, and government organizations. With support from the partnership, the use of innovative technology to improve traditional trapping methods allowed feral cats to be removed effectively in the presence of a native species occupying a similar niche. This project shows that strong partnerships, innovative methods, and use of technology can provide the conditions to eradicate invasive species when major barriers to success exist.

Monitoring and Control of Feral Cats on Kaho`olawe: One Step Towards Eradication

The island of Kaho`olawe provides an extraordinary opportunity for conservation and has been referred to in numerous recovery plans for declining populations of Hawaiian avifauna. The feral cat is widely recognized as one of world’s most destructive invasive species and has been implicated in the decline or extinction in a number of native avian species. Of the main 8 Hawaiian Islands, Kaho’olawe presents the most feasible option to eradicate feral cats due to its limited access, remoteness, relatively small size (116 km2), and reserve status. With assistance from a U.S. Fish and Wildlife Service grant, the Kaho`olawe Island Reserve Commission restoration program monitored and controlled feral cats from November 2008 to February 2011. Monitoring techniques included camera traps, tracking stations, spotlight surveys, trapping, and diet and disease analysis. Feral cat density was estimated to be high based on a capture rate and regular monitoring surveys. Cat track observations declined significantly (P < 0.001) during the course of the study. Twenty-two of 46 (47.8%) cats tested positive for seroprevalence to the parasitic protozoan Toxoplasmosis gondii. A major component of prey items consisted of invertebrates mainly comprising centipedes and intertidal crabs. With cooperation from Island Conservation, information gathered helped create an implementation plan for the eradication of feral cats on Kaho`olawe.

Using digital data collection tools to improve overall cost-efficiency and provide timely analysis for decision making during invasive species eradication campaigns

Context Worldwide, invasive vertebrate eradication campaigns are increasing in scale and complexity, requiring improved decision making tools to achieve and validate success. For managers of these campaigns, gaining access to timely summaries of field data can increase cost-efficiency and the likelihood of success, particularly for successive control-event style eradications. Conventional data collection techniques can be time intensive and burdensome to process. Recent advances in digital tools can reduce the time required to collect and process field information. Through timely analysis, efficiently collected data can inform decision making for managers both tactically, such as where to prioritise search effort, and strategically, such as when to transition from the eradication phase to confirmation monitoring. Aims We highlighted the advantages of using digital data collection tools, particularly the potential for reduced project costs through a decrease in effort and the ability to increase eradication efficiency by enabling explicit data-informed decision making. Methods We designed and utilised digital data collection tools, relational databases and a suite of analyses during two different eradication campaigns to inform management decisions: a feral cat eradication utilising trapping, and a rodent eradication using bait stations. Key results By using digital data collection during a 2-year long cat eradication, we experienced an 89% reduction in data collection effort and an estimated USD42 845 reduction in total costs compared with conventional paper methods. During a 2-month rodent bait station eradication, we experienced an 84% reduction in data collection effort and an estimated USD4525 increase in total costs. Conclusions Despite high initial capital costs, digital data collection systems provide increasing economics as the duration and scale of the campaign increases. Initial investments can be recouped by reusing equipment and software on subsequent projects, making digital data collection more cost-effective for programs contemplating multiple eradications. Implications With proper pre-planning, digital data collection systems can be integrated with quantitative models that generate timely forecasts of the effort required to remove all target animals and estimate the probability that eradication has been achieved to a desired level of confidence, thus improving decision making power and further reducing total project costs.

Feral Cats and Biodiversity Conservation: The Urgent Prioritization of Island Management

A great part of the Earth's biodiversity occurs on islands, to which humans have brought a legion of invasive species that have caused population declines and even extinctions. The domestic cat is one of the most damaging species introduced to islands, being a primary extinction driver for at least 33 insular endemic vertebrates. Here, we examine the role of feral cats in the context of the island biodiversity crisis, by combining data from reviews of trophic studies, species conservation status reports, and eradication campaigns. The integration of these reviews permits us to identify priority islands where feral cat eradications are likely to be feasible and where cats are predicted to cause the next vertebrate extinctions. Funding agencies and global conservation organizations can use these results to prioritize scarce conservation funds, and national and regional natural resource management agencies can rank their islands in need of feral cat eradication within a global context.

Contingent absences account for range limits but not the local abundance structure of an invasive springtail

Understanding spatial variation in abundance is essential for forecasts of responses to environmental change impacts on diversity and the consequent conservation actions. However, few studies have sought to distinguish the causal basis of abundance structure and range limits. Here we do so for an invasive springtail species, Pogonognathellus flavescens, in a cold temperate island setting. Local microclimate variables and physiological tolerances of this habitat generalist suggest that it should be widely distributed across a range of habitats below 200 m elevation on the island. By contrast, island‐wide and local abundance surveys show that it is restricted to indigenous Poa cookii tussock grassland habitats in the southeast. Preference for this habitat is correlated with the presence of vertebrates and a threshold response to soil Ca and pH, with preference for low values of both. Habitat specificity may be the consequence of a founder effect because the species is characterized by only a single mitochondrial COI haplotype. Nonetheless, P. flavescens is absent from many other areas of suitable P. cookii habitat around the island. The most plausible explanation appears to be dispersal limitation (i.e. a contingent absence). Despite high locomotion speeds measured in the laboratory at optimum and mean annual soil temperatures (0.97 and 0.42 cm s−1 at 26°C and 6.5°C, respectively), dispersal in the field indicated that >100 yr would be required to reach all available habitat in the absence of jump dispersal, for which few vectors exist. Thus, current range limits are set by dispersal limitation (i.e. contingent absences) whilst abundance structure is a function of variation in soil substrate quality. Edaphic variables both in this species and other soil invertebrates may be more significant than climatic factors in determining abundance and occurrence, indicating that they should be routinely included in species distribution models. Low genetic diversity and high habitat preference suggest that in the absence of introduction of additional individuals, the species will not spread rapidly at the island. However, over time, the widening distribution of its preferred habitat, P. cookii, as a consequence of a major management intervention (the eradication of feral cats), may enable it to colonize all suitable areas.

Getting Ready for the Next Step: The Eradication of Feral Cats on Large and Highest Priority Mexican Islands

Mexican islands’ biodiversity is very rich and diverse; several reptile, bird, and mammal endemic species live on them. However, ecological and evolutionary processes have been negatively affected by invasive species. To date, more than 20 island endemics, including mammals, birds and reptiles, have gone extinct on Mexican islands. As a very opportunistic predator that adapts easily to different environments, the feral cat is one of the most lethal invasive species. Restoration of island ecosystems can be achieved effectively by the eradication of this noxious species. In Mexico, 18 islands (<400 km2) have been cleared of feral cats using traditional techniques, i.e. trapping and hunting. These techniques are still being implemented on smaller islands or on islands where populations are small. Nevertheless, on big islands with complex terrain and topography, varied habitats and climates, and with non-target species, there are challenges to overcome. This includes Socorro (130 km2), Cerralvo (135 km2), and Guadalupe (240 km2) Islands. To achieve successful cat eradications on these islands, dispersion of toxic baits will be necessary. Currently, bait trials are being developed by Grupo de Ecologia y Conservacion de Islas, A.C., and supported by Australian and New Zealand institutions, as part of island-specific eradication plans. To date, these studies comprise feral cat and native species ecology for Cerralvo and Socorro Islands. All data gathered is valuable for eradication planning.

A Trap Monitoring System to Enhance Efficiency of Feral Cat Eradication and Minimize Adverse Effects on Non-Target Endemic Species on San Nicolas Island

Author(s): Will, David; Hanson, Chad C.; Campbell, Karl J.; Garcelon, David K.; Keitt, Brad S. | Abstract: Feral cats have significant negative impacts on island ecosystems and are a major threat to resident seabird populations. In an attempt to restore populations of Brandt’s Cormorants, western gulls, and other native species on San Nicolas Island, California, feral cats were targeted for eradication. In over 83 successful feral cat eradications from islands, removal by padded leg-hold traps was the most commonly used eradication technique. However, the size of San Nicolas, 5,896 ha (14,562 acres) and the presence of g600 diminutive (average 1.7 kg) endemic island fox presented challenges. A telemetry-based trap monitoring system was developed to remotely check trap status, decrease staff time spent checking traps, and decrease response time to captured animals to limit fox injuries and mortalities due to exposure. This system enabled a team of 6 staff to maintain daily checks of approximately 250 traps and have a response time to captures of l60 minutes during daylight hours. Field staff were trained to assess fox health in the field, and a mobile veterinary hospital was established on island to treat any injuries. The trap monitoring system was composed of transmitter units connected to traps, an island-wide repeater system, a GIS database with field PDA data collection, and a user interface hosted on a local internet network. When activated, each transmitter sent a trapspecific ID code every 4 hours, indicating it was operational. When sprung, a modified ID code was transmitted every 30 minutes until the trap transmitter was reset. Repeaters relayed trap status data, both to a dedicated PC where a set of scripts filtered the raw data to find capture events, and simultaneously to the internet. A web-based software user interface was designed to combine capture events with location information from a GIS database, allowing field staff to quickly identify which traps were sprung and plan the most effective route between all sprung traps. Ultimately, this system was a powerful adaptive management tool that increased staff efficiency and minimized effects on non-target species.

The Removal of Feral Cats from San Nicolas Island: Methodology

Feral cats are considered one of the most detrimental invasive species within island ecosystems. Non-native feral cats have been on San Nicolas Island (5,896 ha, or 14,562 acres) since at least 1952. In an effort to counter the negative impacts of feral cats on marine and terrestrial birds, the San Nicolas seabird restoration project, with the goal of eradicating cats, was initiated in June 2009. Although aimed at seabird restoration, feral cat eradication is expected to aid in the protection of endemic terrestrial species, including the federally threatened island night lizard, federally threatened western snowy plover, a subspecies of deer mouse, and the state threatened island fox. Methods including the use of altered padded leg-hold live traps, detection dogs, and hunting are being utilized to deliver a successful eradication within a short window of opportunity. In addition, a trap monitoring system, operated in tandem with field PCs and GIS, has proven effective in managing large numbers of traps. Since initiation, a rotation of staff has provided an average of 6 field personnel on-island at any one time to staff the project continuously over 10 months. Eradication was complicated by the similarly sized island fox, rugged topography, restricted access to parts of the island by Navy activities, marine mammal presence on the beaches, and sea and shore birds nesting and roosting. Island eradications require multiple methods to effectively remove all cats, and operations on larger islands benefit from the intensive use of management tools such as GIS. The systems developed on the San Nicolas Seabird Restoration Project will advance the global effort to reduce the threats of invasive species, particularly feral cats.

The eradication of feral cats from Ascension Island and its subsequent recolonization by seabirds

The introduction of mammal predators to islands often results in rapid declines in the number and range of seabirds. On Ascension Island the introduction of cats in 1815 resulted in extirpation of large seabird colonies from the main island, with relict populations of most species persisting only in cat-inaccessible locations. We describe the eradication of feral cats from this large and populated island. The campaign had to minimize risk to humans and maintain domestic animals in a state that prevented them re-establishing a feral population. Feral cat numbers declined rapidly in response to the strategic deployment of poisoning and live trapping, and cats were eradicated from the island within 2 years. During the project 38% of domestic cats were killed accidentally, which caused public consternation; we make recommendations for reducing such problems in future eradications. Since the completion of the eradication campaign cat predation of adult seabirds has ceased and five seabird species have recolonized the mainland in small but increasing numbers. Breeding success of seabirds at Ascension was low compared to that of conspecifics elsewhere, and the roles of food availability, inexperience of parent birds and black rat predation in causing this warrant further investigation. It is likely that the low breeding success will result in the rate of increase in seabird populations being slow.

Evidence of mouse attacks on albatross chicks on sub-Antarctic Marion Island

Introduced house mice Mus musculus have recently been discovered to be significant predators of chicks of Tristan albatrosses Diomedea dabbenena and several burrowing petrels at Gough Island. We summarize evidence for mouse attacks on albatross chicks at sub-Antarctic Marion Island, where mice are also the only introduced mammal following the eradication of feral cats Felis catus in the early 1990s. Wounds consistent with mouse attacks have been found on wandering albatrosses Diomedea exulans since 2003 and dark-mantled sooty albatrosses Phoebetria fusca in 2009. To date, attacks on wandering albatross chicks have been infrequent, affecting &lt;1% of chicks in study colonies, and only about half of the attacks have been fatal. Small chicks may also die when mouse burrows collapse under chicks, trapping them. Mouse attacks appear to be a recent phenomenon, supporting the contention that mice pose a significant threat when they are the only introduced mammal species. Ongoing monitoring is needed to assess whether the impacts of mice increase over time. Our observations add impetus to calls for the eradication of mice from Marion Island.