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House mice (Mus musculus) are an invasive species on Auckland Island in the New Zealand subantarctic and planning for their eradication is underway. Mast seeding events cause rodent populations to irrupt, though little is known about this phenomenon in snow tussock grass (Chionochloa spp.) systems on Southern Ocean islands. The aim of this study was to understand population fluctuations of mouse abundance on Auckland Island for the 2 years following a mast event, and with which tools to monitor abundance, to inform planning of bait application for eradication. Mouse populations were studied using kill and live trapping at two sites on Auckland Island, and mouse density was estimated using spatially explicit capture-recapture models. Mouse population density was highest during summer mast seeding of Chionochloa antarctica and then declined the following winter and subsequently remained low for the following year. Breeding remained seasonal, with a pulse in early summer and a very low level continuing through winter in both years, regardless of mast conditions. These results are similar to those from other cool temperate Southern Ocean islands where seasonal resource availability appears to drive breeding. Throughout the study the capture probability of mice was generally higher when population density was lower, which highlights that conclusions about population trends could be misleading if abundance indices are not calibrated to measures of population density. Mouse eradication should preferentially take place outside of a mast event but would likely still succeed during and following a mast event. Our work fills a key knowledge gap about rodent population trends during mast events for Southern Ocean islands, which is particularly important where eradications are planned. [ABSTRACT FROM AUTHOR]

Primary poisoning is an important method to ensure the successful eradication of cats (Felis catus) from large islands. Poison bait options for feral cat eradications and landscape-scale control in New Zealand are limited at present. As part of the development of a toxic bait for cats that can be aerially distributed, a nontoxic palatability trial was undertaken on Auckland Island to compare three types of prototype meat-based bait and one currently registered fishmeal polymer pellet for their palatability to feral cats and non-target species. Degradation rates of baits over a range of environmental conditions were also estimated by taking photographs of baits at regular intervals and inferring degradation from visual appearance of baits over time. Fourteen individual cats were sighted on 144 occasions with all individuals consuming at least one bait type. Results show that the three prototype meat baits were significantly more palatable than the fishmeal polymer baits. No native non-target animals were observed consuming any of the baits during the trial. Fishmeal polymer baits degraded at a slower rate than the meat-based matrices. Palatability results for the meat-based matrices are encouraging. Further trials of a toxic meat-based bait will be required to assess efficacy in pursuit of a registered product for wider use. [ABSTRACT FROM AUTHOR]

Auckland Island, the fifth largest island in New Zealand, is the only island in New Zealand’s subantarctic region where introduced mammalian pests remain (pigs, Sus scrofa; mice, Mus musculus; cats, Felis catus). The island has unique biodiversity and is a key site for progressing New Zealand’s goal to be free of several introduced predators by 2050. Recent island eradication successes have rekindled interest in eradicating pests from Auckland Island, and for the first time considering all three pests in one project. Over a 3-year period, we tested the feasibility of eradicating pigs, mice and cats by looking at what it would take to succeed, rather than what we could practically deliver with the tools we currently have. We proposed adaptations to current methods and used an evidence-based approach by undertaking large-scale field trials to test uncertainties and emerging technologies in-situ. We gathered data and evaluated proposed methods against five established principles of eradication while considering the logistics and infrastructure requirements of the project. Eradicating pigs, mice and cats from Auckland Island is worthwhile and feasible but dependent on further development of emerging technologies and capabilities for efficient delivery with an acceptable level of risk. Three eradication operations are required with specific sequencing and timing, supported by initial establishment of infrastructure. The project needs a large investment spread over 8 to 10 years to yield permanent and internationally important benefits with low ongoing cost to sustain. The feasibility study exposed the project’s scale and was used to inform decision makers, who postponed the work in 2020 in response to the economic impacts of COVID-19. The study focusses future preparations on identified planning issues and dependencies to progress project readiness in anticipation of it being launched when economic conditions allow. [ABSTRACT FROM AUTHOR]

As a major threat to New Zealand’s biodiversity, feral cats (Felis catus) are the subject of planned eradications on a number of offshore islands, including Rakiura Stewart Island. We used camera traps to estimate population density of feral cats on the north-east coast of Rakiura, and to investigate their movement behaviour and detection probability. We also used camera footage to compare the consumption of two types of non-toxic sausage baits (chicken and rabbit) with a view to future use of toxic baits. Population density of feral cats was likely between 1 and 2 cats per km². Non-target species (rats and possums) removed more than half the baits, greatly reducing bait availability for feral cats. Deer and birds (including kiwi) encountered baits but did not eat them. Cats had an apparent preference for chicken over rabbit baits, although small sample sizes prevent firm conclusions. Both bait types appeared to decline rapidly in palatability, and no baits were consumed by cats more than 5 days after deployment. Future trials and baiting regimes should consider ways to improve bait availability. Increased bait density, exclusion of rats and possums and/or more frequent replacement of baits will likely increase encounter rates by feral cats. [ABSTRACT FROM AUTHOR]

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. Second, we used resource selection functions with generalised linear mixed models to identify seasonal patterns of space use associated to topographic, vegetation and other landscape predictors. Lastly, we quantified cats daily movement rates within home ranges. Average home range size was larger than on other offshore islands and mainland New Zealand, which might relate to lower cat densities and the abundance and predictability of food resources on the island. Cats mostly selected mosaic areas of forest, shrubs and tall tussocks near the coast, and in predominantly flat areas or nearby steep cliffs, which are all typical habitats of seabirds and terrestrial birds. Cats also selected alpine short tussocks during the cold season, likely related to the upsurge of mice (Mus musculus) due to tussock mast seeding and to transiting to steep cliffy areas. Male cats had home ranges that were larger, contained more core areas, and covered longer daily distances in the warm season than females, which might be associated with different breeding and reproductive behaviour. Eradication tools will need to target all habitats on Auckland Island with increased efforts in areas of identified higher use by cats. Understanding aspects of pest species’ spatial ecology on offshore islands worldwide can assist decision-makers in optimising eradication programs such as Predator Free 2050 in New Zealand. [ABSTRACT FROM AUTHOR]

This paper is based on anthropological research in three New Zealand cytogenetics laboratories involving participant observation carried out over three months and interviews with sixteen cytogeneticists in order to elucidate the distinctive characteristics of their views on the social consequences of their work in prenatal genetic testing. The discourses employed by cytogeneticists to describe their work are placed against other discourses in the contemporary debate surrounding prenatal genetic testing, i.e. clinical, ethical, feminist, social science and disability rights. In general, cytogeneticists frame their moral responsibilities in terms of the need to carry out what we have termed 'distanced care' of both the mothers being tested and the foetal cells which they cultivate in the laboratories. Certain paradoxes arise in these accounts of their work however, such as the idea of distanced care versus their demonstrated personalisation of the foetal cells with which they work and also between their burdensome awareness of the consequences for individual women of their karyotyping and their repeated references to the ethical and social consequences of their work as being determined by society not by their own actions.