Density and home range of feral cats in north-western Australia

2015 ◽  
Vol 42 (3) ◽  
pp. 223 ◽  
Author(s):  
Hugh W. McGregor ◽  
Sarah Legge ◽  
Joanne Potts ◽  
Menna E. Jones ◽  
Christopher N. Johnson

Context Feral cats (Felis catus) pose a significant threat to biodiversity in Australia, and are implicated in current declines of small mammals in the savannas of northern Australia. Basic information on population density and ranging behaviour is essential to understand and manage threats from feral cats. Aims In this study, we provide robust estimates of density and home range of feral cats in the central Kimberley region of north-western Australia, and we test whether population density is affected by livestock grazing, small mammal abundance and other environmental factors. Methods Densities were measured at six transects sampled between 2011 and 2013 using arrays of infrared cameras. Cats were individually identified, and densities estimated using spatially explicit capture–recapture analysis. Home range was measured from GPS tracking of 32 cats. Key results Densities were similar across all transects and deployments, with a mean of 0.18 cats km–2 (range = 0.09–0.34 km–2). We found no evidence that population density was related to livestock grazing or abundance of small mammals. Home ranges of males were, on average, 855 ha (±156 ha (95% CI), n = 25), and those of females were half the size at 397 ha (±275 ha (95% CI), n = 7). There was little overlap in ranges of cats of the same sex. Conclusions Compared with elsewhere in Australia outside of semiarid regions, feral cats occur at low density and have large home ranges in the central Kimberley. However, other evidence shows that despite this low density, cats are contributing to declines of small mammal populations across northern Australia. Implications It will be very difficult to reduce these already-sparse populations by direct control. Instead, land-management practices that reduce the impacts of cats on prey should be investigated.

Author(s):  
Aenea Saanya ◽  
Rhodes Makundi ◽  
Loth Mulungu ◽  
Apia Massawe

Home ranges play an important role in the ecology of small mammals in understanding the driving factors for variations between species, including; mating patterns, foraging behavior and habitat use. We investigated the abundance, relative home ranges and species-habitat association of small mammal species in the Nyerere National Park. Two habitats; closed woodland and seasonal riverine forest were selected and in each habitat two grids of 70m x 70m were established. The Capture Mark Recapture technique was deployed. From July 2018 to June 2020 a total of 732 small mammal individuals belonging to 19 species were captured. Of the 19 species captured, 12 were rodents, 2 insectivores, 4 carnivores; and 1 primate. Acomys ngurui abundance was not statistically significant different between habitats (W = 220, df = 1, p = 0.144) and across seasons (F(2, 45) = 1.41, p = 0.2547)). While, Mastomys natalensis and Lemniscomys rosalia were statistically significant different (W = 407, p = 0.01 and W=430.5, p=0.002 respectively) between habitats and across seasons (F(2,45) = 4.352, p = 0.019 and F(2,45) = 6.321, p = 0.0038 respectively). Acomys ngurui had the largest mean home range size (1,087.58 m2) than L. rosalia (831.55 m2) and M. natalensis (166 m2) with overlaps being recorded in habitats and across seasons. Most small mammals were associated with seasonal riverine forest. We conclude that, small mammal species abundance and home ranges vary with habitats and seasons for individual species in the Nyerere National Park. We recommend to the management of the park to consider small mammals in their general management plan.


2009 ◽  
Vol 36 (5) ◽  
pp. 422 ◽  
Author(s):  
K. E. Moseby ◽  
J. Stott ◽  
H. Crisp

Control of introduced predators is critical to both protection and successful reintroduction of threatened prey species. Efficiency of control is improved if it takes into account habitat use, home range and the activity patterns of the predator. These characteristics were studied in feral cats (Felis catus) and red foxes (Vulpes vulpes) in arid South Australia, and results are used to suggest improvements in control methods. In addition, mortality and movement patterns of cats before and after a poison-baiting event were compared. Thirteen cats and four foxes were successfully fitted with GPS data-logger radio-collars and tracked 4-hourly for several months. High intra-specific variation in cat home-range size was recorded, with 95% minimum convex polygon (MCP) home ranges varying from 0.5 km2 to 132 km2. Cat home-range size was not significantly different from that of foxes, nor was there a significant difference related to sex or age. Cats preferred habitat types that support thicker vegetation cover, including creeklines and sand dunes, whereas foxes preferred sand dunes. Cats used temporary focal points (areas used intensively over short time periods and then vacated) for periods of up to 2 weeks and continually moved throughout their home range. Aerial baiting at a density of 10 baits per km2 was ineffective for cats because similar high mortality rates were recorded for cats in both baited and unbaited areas. Mortality was highest in young male cats. Long-range movements of up to 45 km in 2 days were recorded in male feral cats and movement into the baited zone occurred within 2 days of baiting. Movement patterns of radio-collared animals and inferred bait detection distances were used to suggest optimum baiting densities of ~30 baits per km2 for feral cats and 5 per km2 for foxes. Feral cats exhibited much higher intra-specific variation in activity patterns and home-range size than did foxes, rendering them a potentially difficult species to control by a single method. Control of cats and foxes in arid Australia should target habitats with thick vegetation cover and aerial baiting should ideally occur over areas of several thousand square kilometres because of large home ranges and long-range movements increasing the chance of fast reinvasion. The use of temporary focal points suggested that it may take several days or even weeks for a cat to encounter a fixed trap site within their home range, whereas foxes should encounter them more quickly as they move further each day although they have a similar home-range size. Because of high intra-specific variability in activity patterns and home-range size, control of feral cats in inland Australia may be best achieved through a combination of control techniques.


Oryx ◽  
1995 ◽  
Vol 29 (1) ◽  
pp. 35-42 ◽  
Author(s):  
E. Suárez ◽  
J. Stallings ◽  
L. Suárez

A small-mammal hunting study was carried out in north-western Ecuador from October 1992 to October 1993, employing interview and trapping methods to document rodent and marsupial hunting by Chachi Indian and Afroecuadorian families. Based on 109 family interviews in 28 communities, it was determined that log-fall traps were used around family gardens and along forest trails. Afroecuadorian families used more than twice the number of traps than Chachis and trap lines of both ethnic groups were left open for approximately 6 days per trapping session. Chachi families left trap lines closed twice sas long as Afroecuadorian families. There were 857 individuals of seven rodent and four marsupial species trapped during the study, with Proechimys semispinosus representing more than 50 per cent of the small mammals trapped.


2012 ◽  
Vol 34 (1) ◽  
pp. 59 ◽  
Author(s):  
Kelly Rayner ◽  
Brian Chambers ◽  
Brent Johnson ◽  
Keith D. Morris ◽  
Harriet R. Mills

Knowledge of the ecology of the chuditch (Dasyurus geoffroii) is largely restricted to its distribution in mesic jarrah forests. There is a need for information regarding its ecology in semiarid zones where rainfall and consequently productivity are lower than mesic forests. Given that spatial requirements are strongly influenced by resource availability, it was expected that the chuditch in the semiarid zone would be present at lower densities and would have larger core home ranges (defined by daytime refuges) than those in the jarrah forests. The diet was also investigated by examining the contents of scats. Chuditch at Forrestania were trapped and six individuals were radio-tracked. The population density was one-third that of the lowest estimate reported from the jarrah forest and core home-range estimates were substantially larger, particularly for males. The diet included mammals, birds, reptiles, invertebrates, plants and rubbish, which was consistent with it being a generalist predator. Chuditch did have greater spatial requirements than in the jarrah forest, therefore different management regimes may be needed for populations occurring in the semiarid zone.


1992 ◽  
Vol 19 (6) ◽  
pp. 707 ◽  
Author(s):  
NPE Langham

The activity patterns of a resident population of 15 feral cats (Felis catus L.) on New Zealand farmland were investigated from March 1984 until February 1987 by radiotelemetry. Females could be divided into two separate groups: (1) those denning in barns and (2) those denning in the swamp and willows. Females denning in barns were mainly nocturnal except in spring and summer when rearing kittens. Barn cats moved significantly further between dusk and dawn, except in autumn-winter, than those denning in swamp and willows which were active over 24 h. When not breeding, related females occupied the same barn. In both groups, the home range of female relatives overlapped. Males ranged over all habitats, and dominant adult males moved significantly further and had larger home ranges than other males in all seasons, except in summer when they rested, avoiding hot summer days. Only adult males were active during the day in spring and autumn-winter. The importance of a Zeitgeber in synchronising cat activity with that of the prey is examined. The significance of female den site is discussed in relation to proximity of food, predators, social behaviour and male defence.


2016 ◽  
Vol 43 (4) ◽  
pp. 348 ◽  
Author(s):  
Juliey Beckman ◽  
Alan Lill

Context The number of teats that a female agile antechinus (Antechinus agilis) possesses effectively determines her initial litter size. In the Otway Ranges, south-eastern Australia, numerous separate populations in which all females have either six or 10 teats occur fairly close together in similar, contiguous forest at comparable altitudes and latitudes. Six-teat and 10-teat females have a similar mean mass, but the latter have a 1.7 × greater reproductive potential and so should have a greater nutritional requirement while raising young than do six-teat females. Theoretically, they could meet this requirement by occupying larger and/or more exclusive home ranges during breeding than do six-teat females do (provided that their food-resource abundance is comparable), albeit at a greater energetic cost. Aims The aim of the study was to determine whether 10-teat A. agilis females occupied larger and less overlapping home ranges than did six-teat females. To interpret the findings more meaningfully, it was necessary to compare food abundance and habitat characteristics in areas occupied by the two phenotypes. Methods The investigation was conducted in six-teat and 10-teat A. agilis areas in cool temperate forest over 22 months. Population density was determined by mark–recapture methods and arthropod prey biomass and abundance by pitfall trapping. Vegetation structure and plant-taxa abundance and diversity were determined by standard plant-survey methods. Female home-range estimates determined by radio-tracking were based on 95% minimal convex polygons (MCP) and kernel analysis. Home-range overlap was based on 80% MCP range determinations and core areas were calculated from utilisation plots. Key results Female population density was 2.5 × lower in exclusively 10-teat than in exclusively six-teat populations. Radio-tracked 10-teat females’ home ranges less commonly overlapped those of identified female neighbours and, on average, were 1.5 × larger than ranges of six-teat females. Food abundance and composition was similar in six-teat and 10-teat areas, but ground cover was denser and more complex in the latter areas. Conclusions Food-resource availability was similar in the six-teat and 10-teat phenotype areas, so the larger, and probably more exclusive, home ranges of 10-teat females could reflect greater nutritional requirements resulting from having larger litters, and account for their lower population density. Implications The A. agilis teat-number variation pattern in the Otways may be a rare, visible example of ongoing incipient speciation. This makes it of great scientific and conservation value and it is important to document how the phenomenon operates.


2015 ◽  
Vol 37 (2) ◽  
pp. 219 ◽  
Author(s):  
Tim S. Doherty

The diet of sympatric dingoes and feral cats was studied in the semiarid southern rangelands of Western Australia. A total of 163 scats were collected over a period of 19 months. Rabbit remains were the most common food item in cat scats, followed by reptiles, small mammals and birds. Macropod remains were the most common food item in dingo scats, followed by rabbits and birds. Dingo scats did not contain small mammal remains, and infrequently contained arthropod and reptile remains. Cat and dingo scats contained remains from 11 and six mammal species, respectively. Of the small mammals, cat scats contained rodent remains more frequently than those of dasyurids. Dietary diversity of cats was higher than for dingoes and dietary overlap between the two species was relatively low.


1996 ◽  
Vol 23 (4) ◽  
pp. 401 ◽  
Author(s):  
SS Comport ◽  
SJ Ward ◽  
WJ Foley

The socio-ecology of Petauroides volans has been studied for subtropical and temperate populations, but not for the northern tropical subspecies, Petauroides volans minor. Data on the effects of a high population density on home ranges, time budgets and food-tree use were obtained by means of radio-telemetry. Three techniques were used to estimate home-range area (kernel, MCP and harmonic mean) and the kernel method was preferred. Estimates of home-range area (defined by the 95% kernel) gave mean values of 2.5 and 1.3 ha for males and females, respectively. Broad overlap of home ranges of males was observed, which has not been reported previously for populations of P. volans. Behaviour patterns for males and females were similar to those in previous studies, although the mating system may differ, possibly because of the high population density. Dietary patterns were similar to those previously reported for this species, the most important food items being young leaves and flower buds of particular eucalypt species, notably Eucalyptus acmenoides.


1995 ◽  
Vol 22 (3) ◽  
pp. 299 ◽  
Author(s):  
V Mirmovitch

Feral cats were studied for 10 months in a residential area in Jerusalem and their spatial distribution compared during two 1-month periods, the first in the autumn prior to the mating season and the second during the mating season (winter). Cat locations were recorded by direct observations, and home-range sizes were calculated with the minimum convex polygon method. No significant change in home-range size of adult males or females was found between the 2 periods. Young males expanded their home ranges considerably during their first mating season. Home ranges of males were significantly larger than those of females in both periods (0.56 and 0.30 ha, respectively, in autumn; 0.75 and 0.27 ha in winter). The home ranges of both sexes overlapped considerably with individuals of the same sex. Overlap among home ranges of females indicated a group pattern. High overlap (80%) was found among females that fed from the same set of garbage bins with similar frequency. Lower overlap (20%) was found between individual females that shared only a subset of their food resources and used it with different frequency. It is suggested that the distribution of food patches (garbage bins), the amount of food available and the rate of food renewal determined the cats' spatial organisation.


2015 ◽  
Vol 42 (8) ◽  
pp. 705 ◽  
Author(s):  
Lily Leahy ◽  
Sarah M. Legge ◽  
Katherine Tuft ◽  
Hugh W. McGregor ◽  
Leon A. Barmuta ◽  
...  

Context Changes in abundance following fire are commonly reported for vertebrate species, but the mechanisms causing these changes are rarely tested. Currently, many species of small mammals are declining in the savannas of northern Australia. These declines have been linked to intense and frequent fires in the late dry season; however, why such fires cause declines of small mammals is unknown. Aims We aimed to discover the mechanisms causing decline in abundance of two species of small mammals, the pale field rat, Rattus tunneyi, and the western chestnut mouse, Pseudomys nanus, in response to fire. Candidate mechanisms were (1) direct mortality because of fire itself, (2) mortality after fire because of removal of food by fire, (3) reduced reproductive success, (4) emigration, and (5) increased mortality because of predation following fire. Methods We used live trapping to monitor populations of these two species under the following three experimental fire treatments: high-intensity fire that removed all ground vegetation, low-intensity fire that produced a patchy burn, and an unburnt control. We also radio-tracked 38 R. tunneyi individuals to discover the fates of individual animals. Key results Abundance of both species declined after fire, and especially following the high-intensity burn. There was no support for any of the first four mechanisms of population decline, but mortality owing to predation increased after fire. This was related to loss of ground cover (which was greater in the high-intensity fire treatment), which evidently left animals exposed to predators. Also, local activity of two predators, feral cats and dingoes, increased after the burns, and we found direct evidence of predation by feral cats and snakes. Conclusions Fire in the northern savannas has little direct effect on populations of these small mammals, but it causes declines by amplifying the impacts of predators. These effects are most severe for high-intensity burns that remove a high proportion of vegetation cover. Implications To prevent further declines in northern Australia, fire should be managed in ways that limit the effects of increased predation. This could be achieved by setting cool fires that produce patchy burns, avoiding hot fires, and minimising the total area burnt.


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