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Context: Animal-borne devices can affect animal survival, reproduction, and behaviour through both the addition of weight and bulk and the direct effects of initial and subsequent capture. Researchers commonly employ a general rule of thumb that weight of the device must be less than 5% of bodyweight for terrestrial animals; however, this threshold has little empirical basis. Aims: We evaluated the effects of environmental variables, repeated capture, and weight of animal-borne devices on bodyweight in free-ranging feral cats. Methods: We recaptured feral cats at varying frequencies, wearing GPS and/or VHF collars that ranged from 0.29% to 4.88% of bodyweight, and recorded change in cat weight over time. Key results: Collar weight as a percentage of bodyweight was not a significant predictor of feral cat weight change. Rather, change in bodyweight was best described by a negative relationship with an increasing temperature and number of captures, and a positive relationship with time since collar attachment. Conclusions: Capture had a significant influence on feral cat weight but collar weights up to 5% of bodyweight did not significantly contribute to weight loss. However, the absence of control cats without collars hindered definitive conclusions on the effect of collar weight on cat weight change. Implications: Researchers should space capture and handling events more than 30 days apart to reduce effects of weight loss from capture and handling. Researchers should also consider increasing collar weight and reducing frequency of capture (where collars are less than 5% of bodyweight), particularly if cat bodyweight is a parameter of interest. Feral cats are one of the most harmful invasive species in Australia, and are often caught and collared as part of scientific study to investigate their impacts and inform management. We evaluated the impacts of this process on feral cats. Even though collar weight had no impact, repeated recaptures reduced cat weight. Researchers should consider prioritising fewer capture and handling events over collar-weight reductions, or offset the effect of repeated capture by allowing recovery time greater than 30 days before subsequent recapture attempts. Photograph by Darcy Whittaker. [ABSTRACT FROM AUTHOR]

Context: Populations of native mammals are declining at an alarming rate in many parts of tropical northern Australia. Fire regimes are considered a contributing factor, but this hypothesis is difficult to test because of the ubiquity of fire. Aims: This preliminary study investigated relative abundance and richness of small mammals on a gradient of fire regimes in the Uunguu Indigenous Protected Area (north Kimberley, Australia). Methods: Species were sampled using 40 unbaited camera traps, positioned for a year on 20 transects crossing the rainforest–savanna boundary at locations with comparable environment and geology but varying fire history. The relative importance of the factors 'fire frequency', 'late dry season fire frequency', 'time since burnt' and 'vegetation type' as predictors of the number of small mammal species and detections was tested using Spatial Generalised Linear Mixed Models to account for spatial autocorrelation. Key results: Nine species of small mammals were observed. Mammals were more abundant and diverse in locations with low overall fire frequency, which was a better predictor than late dry season fire frequency or time since burnt. The model including fire frequency and vegetation explained the highest proportion of total variation in mammal diversity (R 2 = 42.0%), with most of this variation explained by fire frequency alone (R 2 = 40.5%). The best model for number of detections (R 2 = 20.9%) included both factors. Conclusions: In the north Kimberley, small mammals are likely to be more abundant and diverse in areas with low fire frequency. Implications: This natural experiment supports the theory that frequent fires are contributing to the decline of small mammals observed across northern Australia. We evaluated the influence of fire regimes and vegetation type on species richness and detection rate of small mammals in the north Kimberley. Low fire frequency and, to a lesser extent, presence of rainforests were associated with more diverse and abundant small mammal assemblages. These findings support the theory that disturbance regimes might contribute to small-mammal decline. Photograph by Stefania Ondei (camera trap). [ABSTRACT FROM AUTHOR]

Mammals comprise the bulk of the diet of free‐ranging domestic cats Felis catus (defined as including outdoor pet cats, strays, and feral cats) in most parts of their global range. In Australia, predation by introduced feral cats has been implicated in the extinction of many mammal species, and in the ongoing decline of many extant species.Here, we collate a wide range of records of predation by cats (including feral and pet cats) on Australian mammals and model traits of extant, terrestrial, native mammal species associated with the relative likelihood of cat predation. We explicitly seek to overcome biases in such a continental‐scale compilation by excluding possible carrion records for larger species and accounting for differences in the distribution and abundance of potential prey species, as well as study effort, throughout each species' range.For non‐volant species, the relative likelihood of predation by cats was greatest for species in an intermediate weight range (peaking at ca. 400 g), in lower rainfall areas and not dwelling in rocky habitats. Previous studies have shown the greatest rates of decline and extinction in Australian mammals to be associated with these traits. As such, we provide the first continental‐scale link between mammal decline and cat predation through quantitative analysis.Our compilation of cat predation records for most extant, terrestrial, native mammal species (151 species, or 52% of the Australian species' complement) is substantially greater than previously reported (88 species) and includes 50 species listed as threatened by the IUCN or under Australian legislation (57% of Australia's 87 threatened terrestrial mammal species). We identify the Australian mammal species most likely to be threatened by predation by cats (mulgaras Dasycercus spp., kowari Dasyuroides byrnei, many smaller dasyurids and medium‐sized to large rodents, among others) and hence most likely to benefit from enhanced mitigation of cat impacts, such as translocations to predator‐free islands, the establishment of predator‐proof fenced exclosures, and broad‐scale cat poison baiting. [ABSTRACT FROM AUTHOR]