Activity Of Feral Cats Research Articles

Untangling two complementary camera trapping data sets to identify patterns in feral cat activity around a known night parrot population in western Queensland

Feral cats (Felis catus) are a significant predator of native birds in Australia, and a recognised predator for the endangered night parrot (Pezoporus occidentalis). We examined camera trapping data from 2014 to 2020 collected at the Pullen Pullen (night parrot) reserve in south-western Queensland to investigate the spatial and temporal patterns of feral cat activity. These data were collected from two discrete periods, with slightly different foci, and we undertook careful data exploration and refinement to identify a consistent data set. We modelled the relationship between the camera detections and a range of environmental, spatial, and temporal parameters, using logistic regression and two selection criteria (Akaike’s and Bayesian). The final parsimonious model identified that feral cat detection probability decreased with increasing ruggedness and increased as distance to creek lines decreased. Feral cat detection probability also declined over time from camera deployment. In each model the variance component estimates suggested that some influences on cat detection probability remain unexplained. Regardless, our results provide further data on feral cat activity, and therefore information to focus and improve the management of this threat to the night parrot and other significant species on this conservation reserve.

Fox and cat responses to fox baiting intensity, rainfall and prey abundance in the Upper Warren, Western Australia

Context Invasive predators are major drivers of global biodiversity loss. Red foxes (Vulpes vulpes) and feral cats (Felis catus) have contributed to the decline and extinction of many native species in Australia. The deployment of poison baits to control fox populations is a widespread conservation tool, but the effects of baiting intensity, rainfall and prey abundance on baiting effectiveness remain poorly understood. Aims We aimed to understand what influences the association between fox baiting intensity, red fox activity and feral cat activity, to provide inferences about what might affect the effectiveness of fox baiting in reducing fox activity. Methods We used generalised linear models to assess how fox and cat activity changes in relation to fox baiting intensity, rainfall, native prey availability and distance to agricultural land over a 6-year period (2006–13) in the forest ecosystems of the Upper Warren region of south-western Australia. Key results We found that fox activity was negatively associated with rainfall in the previous 12 months and positively associated with prey abundance and fox baiting intensity. We also found an interaction between fox baiting and prey abundance, with fox activity increasing with prey activity in areas of low and moderate baiting intensity, but remaining constant in areas of high baiting intensity. Feral cat activity was positively associated with prey abundance and fox baiting intensity. We found no clear relationship between fox and cat activity. Conclusions The drivers of the association between fox baiting and fox activity are unclear because intense fox baiting was targeted at areas of known high fox abundance. However, our results indicate that intense fox baiting may be effective at decoupling the positive association between fox activity and prey abundance. Our results also suggest a positive association between fox baiting intensity and feral cat activity, thus supporting the case for integrated fox and cat management. Implications We caution interpretation of our results, but note that management of invasive predators could be improved by adjusting the intensity of management in response to changes in environmental conditions and local context (e.g. strategically conducting intense predator management where prey abundance is highest). Improved understanding of these associations requires a monitoring program with sufficient replication and statistical power to detect any treatment effects.

Feral cats use fine scale prey cues and microhabitat patches of dense vegetation when hunting prey in arid Australia

Introduced predators are one of the leading causes of decline in island vertebrates. Understanding how they hunt and kill threatened prey can help improve management activities. Although broadscale features are known to influence predator movement patterns, factors influencing fine scale movement are often overlooked. In particular, the influence of prey cues and microhabitat features has received little attention despite predators spending considerable time hunting prey using a range of visual, olfactory and auditory cues. Using feral cats as a case study, we utilised video and GPS collars combined with ground-truthing to determine if predators use fine-scale prey cues or microhabitat features to hunt in an arid environment. Feral cat activity was comprised of continuous traverses interspersed with periods of stationary activity (GPS clusters) generally less than 40 min in duration. Video collars confirmed that these clusters included the majority of stalk and pounce hunting bouts. Stationary activity was significantly focussed on prominent prey cues such as burrows, foraging digs or warrens of mammalian prey including both exotic (rabbits) and threatened native species (rodents, bilbies and bettongs). Evidence of prey kills was higher at cluster sites. Cats spent significantly more time at microsites with high vegetation cover including single shrubs and trees, suggesting that they use prominent prey cues and patches of thick cover to increase their probability of encountering prey and/or to conceal themselves during hunting or feeding activity. Results suggest prey species with conspicuous cues are at higher risk of predation and this vulnerability could increase over time as resident cats learn to identify the location of prey cues within their home range. Conversely, removing resident knowledgeable predators may reduce predation rates if immigrating predators take time to learn to locate prey cues in their new environment. We urge researchers to investigate fine-scale drivers of movement patterns as this information is likely to be critical for long term management of predator species.

Does management of a top carnivore influence the response of mesopredators and prey to rainfall in arid ecosystems? Evidence for a Baseline Density theory

The removal of apex carnivores from ecosystems can impact the abundance and diversity of species in lower trophic levels. In arid ecosystems, where “bottom up” forces of primary productivity and resource availability strongly affect trophic interactions, the role of “top down” effects is still much debated. This study explored the potential role of an apex predator, the dingo, as a “top down” trophic regulator in Australian arid ecosystems under different levels of primary productivity and dingo management regimes. Consistent with the theory of top down regulation, strong relationships were found between dingo management, dingo activity and fox activity. Dingoes appeared to suppress fox activity where dingoes were uncontrolled or only opportunistically controlled. At sites where dingoes were absent or in low numbers, fox activity was higher, and this inverse relationship persisted regardless of rainfall. The activity of rabbits and small mammals was lower where dingoes were absent and fox activity was high, while the activity of macropods was higher in the absence of dingoes. Feral cat activity did not differ significantly between sites under different dingo management or between years. These results suggest that management of dingoes is a key determinant of fox activity and the activity of some prey under varying levels of productivity. Evidence from this research showed that while the strength of trophic regulation by dingoes may fluctuate, top down effects occurred both prior to and post significant rainfall events. Following this, top down regulation of fox populations during dry periods at sites where dingoes are retained may enable higher and more stable “baseline” densities of small vertebrates, from which a larger and more rapid rate of increase of these prey during the “boom” periods can occur. Understanding the relative strength and interactions of top down and bottom up forces in regulating populations, and under what ecological states the importance of each changes, is important for the long-term conservation of biodiversity in arid regions.

Feral cats are more abundant under severe disturbance regimes in an Australian tropical savanna

Abstract ContextThere is an increasing awareness that feral cats play a key role in driving the ongoing decline of small mammals across northern Australia; yet, the factors that control the distribution, abundance and behaviour of feral cats are poorly understood. These key knowledge gaps make it near-impossible for managers to mitigate the impacts of cats on small mammals. AimsWe investigated the environmental correlates of feral cat activity and abundance across the savanna woodlands of Melville Island, the larger of the two main Tiwi Islands, northern Australia. MethodsWe conducted camera-trap surveys at 88 sites, and related cat activity and abundance to a range of biophysical variables, either measured in the field or derived from remotely sensed data. Key resultsWe found that feral cat activity and abundance tended to be highest in areas characterised by severe disturbance regimes, namely high frequencies of severe fires and high feral herbivore activity. ConclusionsOur results have contributed to the growing body of research demonstrating that in northern Australian savanna landscapes, disturbance regimes characterised by frequent high-severity fires and grazing by feral herbivores may benefit feral cats. This is most likely to be a result of high-severity fire and grazing removing understorey biomass, which increases the time that the habitat remains in an open state in which cats can hunt more efficiently. This is due to both the frequent and extensive removal, and longer-term thinning of ground layer vegetation by severe fires, as well as the suppressed post-fire recovery of ground layer vegetation due to grazing by feral herbivores. ImplicationsManagement that reduces the frequency of severe fires and the density of feral herbivores could disadvantage feral cat populations on Melville Island. A firm understanding of how threatening processes interact, and how they vary across landscapes with different environmental conditions, is critical for ensuring management success.

Vehicle tracks are predator highways in intact landscapes

Roads and other forms of linear infrastructure are rapidly proliferating worldwide, yet little is known about how roads affect the distribution and abundance of predators, particularly in relatively intact landscapes. We used a combination of motion-sensor cameras and spoor surveys to compare dingo, fox and feral cat activity on unsealed vehicle tracks (hereafter: roads) and up to 3 km away, in relatively intact landscapes of the Great Western Woodlands in south-western Australia. We compared predator activity as indicated by independent sightings and spoor observations, in woodlands and shrublands: vegetation types with contrasting permeabilities.Predator activity was observed between 12 and 261 times more frequently on roads compared with off-road for all species studied. Roads also appeared to affect predator activity up to 2.5 km away. Even poorly formed and abandoned roads concentrated predator activity and affected landscape-scale rates of predator observations. The effect of road proximity on predator activity was non-linear and different between vegetation types for dingoes and cats but not foxes. Our results provide new evidence of the effects of roads on predator activity in surrounding landscapes, with interacting effects of vegetation. They also reinforce previous findings e.g. stronger roads preference displayed by dingoes and foxes, than by cats. Roads and other linear infrastructure have strong effects on predator activity within intact landscapes, although further research is needed to characterise the implications for prey species. Road planning or approvals, as well as habitat restoration programs for threatened species, should account for the effects of roads on predator activity.

Feeling the pressure at home: Predator activity at the burrow entrance of an endangered arid‐zone skink

AbstractHabitat modification and invasive species are among the most important contemporary drivers of biodiversity loss. These two threatening processes are often studied independently and few studies have focused on how they interact to influence species declines. Here we assess the predation pressure placed on the threatened great desert skink (Liopholis kintorei) and how this interacts with fire‐induced habitat modifications. We collected daily track data of potential predators for 1 month at 30 great desert skink burrow‐systems where vegetation cover varied significantly after experimental burns. We used these data to evaluate potential predation pressure at the burrow‐system and assess whether fire influenced predator pressure. We supplemented this analysis by documenting predation via the inspection of large mammalian predator scats collected from great desert skink habitat. The level of feral cat activity at a burrow‐system entrance was significantly higher than that of any other potential predator, however fire had no effect on the visitation rates of feral cats, dingoes or large snakes to great desert skink burrow‐systems. The remains of great desert skink were found significantly more frequently in feral cat scats, compared to fox and dingo scats. We provide the first direct evidence that feral cats are a significant predator for great desert skink, thus supporting the hypothesis that feral cat predation is a key threatening process. Feral cat activity was not influenced by small‐scale experimental burns, however, this does not preclude an effect of larger scale fires and we recommend further research exploring this possible interaction.

Response of feral cats to a track‐based baiting programme using Eradicat® baits

SummaryThe feral Cat (Felis catus) is a significant threat to Australian fauna, and reducing their impacts is considered an essential action for threatened species conservation. Poison baiting is increasingly being used for the broad scale control of feral cats. In this study, we measured the population response of feral cats to a track‐based baiting programme using Eradicat® baits in the semi‐arid northern wheatbelt region of Western Australia. Over two years, 1500 baits were laid once annually and the response of feral cats was measured using remote cameras in a before–after, control–impact design. There was a significant reduction in feral cat activity in the second year, but not the first. During bait uptake trials, corvids removed the most number of baits, followed by cats and varanids. The lack of a response to baiting in the first year may be due to existing low cat numbers in the baited area and/or the timing of the baiting. We provide a list of key recommendations to help inform future cat baiting programmes and research.

Effects of low-level culling of feral cats in open populations: a case study from the forests of southern Tasmania

Context Feral cats (Felis catus) threaten biodiversity in many parts of the world, including Australia. Low-level culling is often used to reduce their impact, but in open cat populations the effectiveness of culling is uncertain. This is partly because options for assessing this management action have been restricted to estimating cat activity rather than abundance. Aims We measured the response, including relative abundance, of feral cats to a 13-month pulse of low-level culling in two open sites in southern Tasmania. Methods To do this we used remote cameras and our analysis included identification of individual feral cats. We compared estimates of relative abundance obtained via capture–mark–recapture and minimum numbers known to be alive, and estimates of activity obtained using probability of detection and general index methods, pre- and post-culling. We also compared trends in cat activity and abundance over the same time period at two further sites where culling was not conducted. Key results Contrary to expectation, the relative abundance and activity of feral cats increased in the cull-sites, even though the numbers of cats captured per unit effort during the culling period declined. Increases in minimum numbers of cats known to be alive ranged from 75% to 211% during the culling period, compared with pre- and post-cull estimates, and probably occurred due to influxes of new individuals after dominant resident cats were removed. Conclusions Our results showed that low-level ad hoc culling of feral cats can have unwanted and unexpected outcomes, and confirmed the importance of monitoring if such management actions are implemented. Implications If culling is used to reduce cat impacts in open populations, it should be as part of a multi-faceted approach and may need to be strategic, systematic and ongoing if it is to be effective.

Dingoes affect activity of feral cats, but do not exclude them from the habitat of an endangered macropod

Context The loss of large predators has been linked with the rise of smaller predators globally, with negative impacts on prey species (mesopredator release). Recent studies suggest that the dingo, Australia’s top terrestrial predator, inhibits predation on native mammals by the invasive red fox, and therefore reduces mammal extinctions. Feral cats also have negative effects on native mammals, but evidence that dingoes suppress cats remains equivocal. Aims We sought to examine whether dingoes might spatially or temporally suppress the activity of feral cats at a site containing the sole wild population of an endangered macropod subject to feral cat predation (the bridled nailtail wallaby). Methods We used camera traps to compare coarse and fine-scale spatial associations and overlaps in activity times of mammals between August 2009 and August 2010. Key results Dingoes and cats used the same areas, but there was evidence of higher segregation of activity times during wet months. Potential prey showed no spatial avoidance of dingoes. Peak activity times of dingoes and their major prey (the black-striped wallaby) were segregated during the wetter time of year (December to March). We did not find evidence that cats were spatially excluded from areas of high prey activity by dingoes, but there was low overlap in activity times between cats and bridled nailtail wallabies. Conclusions These findings support the contention that fear of dingoes can sometimes affect the timing of activity of feral cats. However, cats showed little spatial avoidance of dingoes at a coarse scale. Implications Control of dingoes should not be abandoned at the site, because the potential moderate benefits of reduced cat activity for this endangered and geographically restricted wallaby may not outweigh the detrimental effects of dingo predation.

Do dingoes suppress the activity of feral cats in northern Australia?

AbstractLarge predators can have profound impacts on community composition. Not only do they directly affect prey abundance, they also indirectly affect prey abundance through their direct effects on smaller predators. In Australia, dingoes fill the role of a large predator and, in southern Australia, have clear impacts on introduced foxes. Their effect on introduced cats, however, is less clear. Here we present data from multiple sites across northern Australia (where foxes are absent), which reveal a negative correlation between cat and dingo activity. This relationship could arise because cats avoid areas where dingoes are active, or because cats are less abundant in areas with high dingo densities, or a combination of both. At a subset of our study sites, we experimentally reduced dingo (but not cat) abundance by poison baiting. This resulted in a 55% drop in dingo activity within 4 weeks of baiting, but without a compensatory increase in cat activity. This suggests the negative correlation between cat and dingo activity is not a simple consequence of cats reactively avoiding areas with higher dingo traffic, but rather, that there are fewer cats in areas where dingoes are more active. This study is a rare demonstration of the potential for dingoes to affect the behaviour and potentially the population size of feral cats, and therefore reduce the impact of feral cats on vulnerable native prey species.

Activity Patterns of Free-Ranging Cats in Brooklyn, New York

Activity patterns of free-ranging cats in Brooklyn, New York, varied with neighborhood, season, and hour of the night. Standardized partial-regression analysis identified temperature, humidity, precipitation, and hour as accounting for 32.6% of feral-cat activity. Cats in the area of private homes included free-ranging pets while those in the area of multiple dwellings were commonly feral. Regardless of neighborhood, nighttime activity was bimodal with peaks occurring at 0100 h and at sunrise. Activity levels declined throughout the autumn and increased in the spring.

Feral cats (Felis catus) as predators of hatchling green turtles (Chelonia mydas)

In many parts of the world feral animals have been reported to have severe effects on marine turtle hatchling production. In this study, green turtle (Chelonia mydas) hatchlings were shown to be an important component of the diet of the feral cat (Felis catus) on Aldabra Atoll, Seychelles, and feral cat activity in the coastal areas was found to be concentrated on the beaches used most intensively by turtles for nesting. The impact of the feral cat's predation on green turtle recruitment could not be determined. However, despite cat predation, the size of the Aldabran green turtle nesting population has increased considerably since human exploitation ceased.