Background: 'Megafire' is an emerging concept commonly used to describe fires that are extreme in terms of size, behaviour, and/or impacts, but the term's meaning remains ambiguous. Approach:We sought to resolve ambiguity surrounding the meaning of 'megafire' by conducting a structured review of the use and definition of the term in several languages in the peer-reviewed scientific literature. We collated definitions and descriptions of megafire and identified criteria frequently invoked to define megafire.We recorded the size and location of megafires and mapped them to reveal global variation in the size of fires described as megafires. Results:We identified 109 studies that define the term 'megafire' or identify a megafire, with the term first appearing in the peer-reviewed literature in 2005. Seventyone (~65%) of these studies attempted to describe or define the term. There was considerable variability in the criteria used to define megafire, although definitions of megafire based on fire size were most common. Megafire size thresholds varied geographically from > 100-100,000 ha, with fires > 10,000 ha the most common size threshold (41%, 18/44 studies). Definitions of megafire were most common from studies led by authors from North America (52%, 37/71). We recorded 137 instances from 84 studies where fires were reported as megafires, the vast majority (94%, 129/137) of which exceed 10,000 ha in size. Megafires occurred in a range of biomes, but were most frequently described in forested biomes (112/137, 82%), and usually described single ignition fires (59% 81/137). Conclusion:As Earth's climate and ecosystems change, it is important that scientists can communicate trends in the occurrence of larger and more extreme fires with clarity. To overcome ambiguity, we suggest a definition of megafire as fires > 10,000 ha arising from single or multiple related ignition events. We introduce two additional terms -gigafire (> 100,000 ha) and terafire (> 1,000,000 ha) -for fires of an even larger scale than megafires.

Burrowing bettongs (Bettongia lesueur) reached high densities within the fenced Arid Recovery reserve. Grazing pressure was assessed by comparing the vegetation inside and outside the reserve during April in 2012, 2013 and 2014. Mean numbers of bettong tracks crossing small 10 m × 1 m plots overnight in the main exclosure were 20 in 2012, decreasing to 4 in 2013 and 3 in 2014. Similar declines were present in the second expansion, where tracks decreased from 7 in 2012 to 3 in 2013 and 2 in 2014. Perennial plant species richness decreased significantly over the study period. Acacia aneura, Acacia ligulata, Atriplex vesicaria, Crotalaria eremaea, Dodonaea viscosa, Enchylaena tomentosa, Maireana astrotricha and Sida ammophila were the most heavily grazed species within the reserve. Overall, more than 25% of plants showed some form of conspicuous grazing. C. eremaea and E. tomentosa showed little damage outside the reserve. Inside the reserve many C. eremaea were dead and heavily browsed and few E. tomentosa remained. Recent recruitment of A. ligulata and D. viscosa was also much higher outside the reserve. High densities of burrowing bettongs were associated with declines in vegetation condition potentially impacting other species and the ecosystem as a whole.

Moon phase and variation in ambient light conditions can influence predator and prey behaviour. Nocturnal predators locate prey visually, and prey may adjust their activity to minimise their predation risk. Understanding how native mammals in Australia respond to varying phases of the moon and cloud cover (light) enhances knowledge of factors affecting species’ survival and inference regarding ecological and population survey data. Over a two-year period within a fenced conservation reserve, in south-eastern Australia, with reintroduced native marsupial predator and prey species (eastern barred bandicoot, southern brown bandicoot, long-nosed potoroo, rufous bettong, Tasmanian pademelon, brush-tailed rock-wallaby, red-necked wallaby, eastern quoll, spotted-tailed quoll, and naturally occurring swamp wallaby, common brushtail possum, common ringtail possum), we conducted monthly spotlight surveys during different moon phases (full, half and new moon). We found an interaction between cloud cover and moon phase, and an interaction of the two depending on the mammal size and class. Increased activity of prey species corresponded with periods of increasing cloud cover. Predators and medium-sized herbivores were more active during times of low illumination. Our findings suggest that moon phase affects the nocturnal activity of mammal species and that, for prey species, there might be trade-offs between predation risk and foraging. Our findings have implications for: ecological survey design and interpretation of results for mammal populations across moon phases, understanding predator and prey behaviour and interactions in natural and modified (artificial lighting) ecosystems, and potential nocturnal niche partitioning of species.

Context On airports, birds often exhibit escape behaviour in response to aircraft. Avian escape behaviours can enable birds to effectively avoid collisions with aircraft, although some are maladaptive and may increase the risk of collision (e.g. erratic flying). Habituation and habituation-like processes among birds potentially mediate the likelihood of aircraft-bird collisions. Moreover, because managers exploit avian escape behaviour to reduce bird–aircraft collision risks, habituation may decrease the efficiency of bird-hazard management. Aims Our aim was to better understand avian behavioural responses to approaching aircraft, which may inform bird-hazard management. Methods We examined the response of Australian magpie, Cracticus tibicen, a species commonly involved in collisions with aircraft, to the noise associated with take-off and landing in three areas: airside, on airport but not airside, and off airport. Key results Magpies responded to aircraft noise in a nuanced way. Take-off produced more responses, and more intense responses, than did landing; both resulted in more frequent, and more intense, responses than did a ‘silent’ control. Responses were least likely, and response latencies were longer, airside, followed by on airport but not airside, and off airport. Intensity of responses was similar across these areas. Conclusions Magpies on the airside were least responsive, and this might influence their strike risk. Implications Given that most wildlife collisions occur during take-off and landing and at low altitudes, and that take-off has greatest overall strike risk, the lack of responsiveness of airside-inhabiting magpies may contribute to collision risk.

Summary We describe a community‐run effort to cull Common Myna (Acridotheres tristis) in Melbourne undertaken with modest funding (overall: $30.14 per trap day, $5.17 per euthanized Common Myna). Trap success (overall, 0.04 birds per trap per day) peaked early in the effort and slowly declined. Trap specificity was high (83.8%) and similar between bait types. Dry cat food captured more Common Myna, and a similar assemblage of animals, to dry dog food. Bread baits captured a broader assemblage of animals. The community‐led trapping programme reduced the mean density of Common Myna and achieved high target specificity with relatively few unintended trap deaths. While long‐term impacts on the population of Common Myna or native birds are yet to be analysed, the results suggest that ongoing effort is required for population suppression.