Context . Aerial baiting using fixed-wing aircraft is an effective method of bait delivery for wild-dog control in remote locations. However, aerial baiting may result in loss of baits to positions that are inaccessible to wild dogs. Attempts, by landholders, to address such bait loss through compensatory baiting may increase baiting costs and potential risks to non-target species.

Aims . To assess bait drift under standard baiting conditions. To assess the availability of aerially deployed baits to wild dogs across several commonly baited landforms in the northern rangelands of Western Australia.

Methods . We determined drift characteristics of baits deployed under standard fixed-wing baiting conditions. We then determined the availability of aerially deployed baits by deploying baits with embedded radio-transmitters across four commonly baited landforms (riparian vegetation, tussock grassland, gorges and breakaways). We then visually assessed the availability of relocated baits (as ‘high’, ‘moderate’ or ‘low’).

Key results . Under standard fixed-wing baiting conditions, on average, baits fell 100.9 m forward, and 8.3 m laterally, from the point-of-release. Across all landforms, most baits (91.8%) were highly available, with a further 7.0% falling into the moderate category and 1.2% in the low category. There were significant differences in bait availability among landforms, with the proportion of moderate-low availability baits greatest in gorges and lowest on tussock grassland.

Conclusions . Within the northern rangelands of Western Australia, bait wastage owing to deployment in inaccessible locations is minimal.

Implications . Compensatory baiting for lost baits is unnecessary and increases costs to land managers.

Context. It is difficult to measure feeding rates for most wild nocturnal mammalian herbivores. Thus, although koalas are a popular species to study, we have a poor understanding of their activity patterns and feeding ecology. Researchers often assume that the trees that koalas occupy during the day indicate feeding preferences, but they may better reflect preferred resting sites.

Aims. We recorded the activities of koalas, with an emphasis on their feeding, particularly when they fed, the trees that they fed from, the number of meals they consumed and the variability in these measurements.

Methods. We continuously monitored eight koalas by audio- and radio-telemetry for 14 consecutive 24-h periods each. We followed two koalas at a time and recorded the trees they visited, when, where and how long they fed, and the size and nutritional composition of the trees in the landscape.

Key results. Individual koalas varied in how many trees they visited, how many meals they ate and how long they spent feeding during each 24-h period. They preferred Eucalyptus globulus trees during the day, but fed mainly at night, with a preference for E. viminalis. The trees that koalas visited during the day were larger than those that they visited at night.

Conclusions. The trees that koalas occupied during the day were poor indicators of their diet preferences, whereas the daily feeding activities of individual koalas varied widely.

Implications. Predicting a koala’s diet from the trees it occupies during the day is fraught with error. Although the trees that koalas rest in are important in the species ecology for reasons other than feeding, we should refrain from using them to predict an animal’s diet. Because feeding activity is difficult to measure, it is probably best done indirectly by analysing leaf-cuticle fragments or waxes in faeces. The substantial day-to-day variation in koala activities also indicates that behavioural and physiological studies of koalas require long monitoring periods – a week or longer.

Context. Common carp (Cyprinus carpio) is a highly invasive freshwater pest fish that has been linked to waterway degradation when it has been introduced and exists at high densities. The deployment of a toxic bait may be a logistically simple tool that wildlife managers could use to reduce carp populations. Rotenone, the piscicide most commonly used in previous attempts to produce a carp bait is very expensive, albeit highly toxic to carp. We investigated the toxicity of two potential alternative piscicides to carp.

Aim. To determine the oral toxicity of two alternative cheaper toxins to carp, cube-root powder (CRP) and sodium nitrite (nitrite).

Methods. CRP or nitrite was administered in an aqueous solution by gavage to lightly sedated captive carp. The aqueous solution consisted of a 30 : 70 mixture (w/w) of the surfactant, Polysorbate 80, to increase the absorption of toxins through the intestine, and water.

Key results. The LD₅₀ of CRP and nitrite in carp was 135.7 mg kg^–1 and 122.0 mg kg^–1, respectively.

Conclusions. Both CRP and nitrite are toxic to carp at dose rates low enough to be incorporated into a piscicide bait for this species.

Implications. Both CRP and nitrite appear to be viable alternative oral piscicides to rotenone for carp and warrant further investigation of delivery in bait.

Context. Over the past few decades, the frequency of wild pig–vehicle collisions (WPVCs) and number of human fatalities associated with these accidents have increased with expanding populations of this species, particularly in regions outside its native distribution.

Aims. To better understand this widespread and growing human safety threat, we quantified habitat attributes associated with 311 WPVC locations occurring between 1983 and 2012 at the Savannah River Site (SRS) in South Carolina, USA, to test the hypothesis that WPVCs occur more frequently in areas proximal to preferred habitats (i.e. riparian and bottomland hardwood habitats).

Methods. At each collision site, we measured the distance to the nearest wetland and stream, as well as the composition of habitats within 100-m and 1699-m buffers. We then contrasted habitat attributes associated with collision sites with those from randomly selected locations along the same roads, to identify habitat characteristics contributing to a higher incidence of these accidents.

Key results. WPVCs were non-randomly distributed across both spatial scales measured, with collisions occurring more frequently in areas of preferred habitat for this species. Specifically, collisions occurred in areas closer to streams and containing less pine forest than at random locations at both spatial scales evaluated.

Conclusions. Similar to vehicle accidents with other ungulate species, our study suggested that vehicle collisions involving wild pigs are spatially clustered around preferred habitat types. Management efforts to reduce vehicle collisions with wild pigs should be focussed in areas where roadways bisect preferred habitats such as stream crossings and bottomland hardwood or other riparian habitats.

Implications. These data will aid in the development of mitigation strategies to reduce the frequency and impacts of WPVCs in areas of high wild-pig densities. However, given the paucity of data on WPVC mitigation, additional research is needed to quantify the efficacy of various methods (e.g. signage, fencing, underpasses) at reducing the frequency and severity of collisions with this species.

Context. Irregular plagues of house mice cause high production losses in grain crops in Australia. If plagues can be forecast through broad-scale monitoring or model-based prediction, then mice can be proactively controlled by poison baiting.

Aims. To predict mouse plagues in grain crops in Queensland and assess the value of broad-scale monitoring.

Methods. Regular trapping of mice at the same sites on the Darling Downs in southern Queensland has been undertaken since 1974. This provides an index of abundance over time that can be related to rainfall, crop yield, winter temperature and past mouse abundance. Other sites have been trapped over a shorter time period elsewhere on the Darling Downs and in central Queensland, allowing a comparison of mouse population dynamics and cross-validation of models predicting mouse abundance.

Key results. On the regularly trapped 32-km transect on the Darling Downs, damaging mouse densities occur in 50% of years and a plague in 25% of years, with no detectable increase in mean monthly mouse abundance over the past 35 years. High mouse abundance on this transect is not consistently matched by high abundance in the broader area. Annual maximum mouse abundance in autumn–winter can be predicted (R² = 57%) from spring mouse abundance and autumn–winter rainfall in the previous year. In central Queensland, mouse dynamics contrast with those on the Darling Downs and lack the distinct annual cycle, with peak abundance occurring in any month outside early spring. On average, damaging mouse densities occur in 1 in 3 years and a plague occurs in 1 in 7 years. The dynamics of mouse populations on two transects ∼70 km apart were rarely synchronous. Autumn–winter rainfall can indicate mouse abundance in some seasons (R² = ∼52%).

Conclusion. Early warning of mouse plague formation in Queensland grain crops from regional models should trigger farm-based monitoring. This can be incorporated with rainfall into a simple model predicting future abundance that will determine any need for mouse control.

Implications. A model-based warning of a possible mouse plague can highlight the need for local monitoring of mouse activity, which in turn could trigger poison baiting to prevent further mouse build-up.

Context.Determining the biodiversity of an area is essential for making targeted conservation decisions. Undertaking surveys to confirm species presence or to estimate population sizes can be difficult, particularly for elusive species. Bats are able to detect and avoid traps, making it difficult to quantify abundance. Although acoustic surveys using bat detectors are often used as a surrogate for relative abundance, the implicit assumption that there is a positive correlation between activity levels and abundance is rarely tested.

Aims.We assessed the effectiveness of surveying techniques (i.e. trapping and acoustic monitoring) for detecting species presence and tested the strength of collinearity among methods. In addition, we tested whether the use of an acoustic lure (a bat-call synthesiser) increased bat-capture rate and therefore species detectability.

Methods.Surveying was carried out over 3 years in central Scotland (UK), in 68 woodlands within predominantly agricultural or urban landscapes.

Key results.There was a significant positive relationship between bat activity recorded on ultrasonic detectors and the relative abundance of Pipistrellus pygmaeus and P. pipistrellus, but not those in the genus Myotis. In general, acoustic monitoring was more effective than trapping at determining species presence; however, to ensure rarer or quiet species are recorded, a complementary approach is required. Broadcasting four different types of echolocation call resulted in a 2–12-fold increase in trapping success across four species of insectivorous bat found in the study region. Whereas lure effectiveness remained unchanged for female P. pygmaeus over time, there was a marked increase in the number of males captured using the lure throughout the summer (May to September).

Conclusions.In the present study, we have demonstrated a variety of ways to increase surveying efficiency, which can maximise the knowledge of diversity in an area, minimise wildlife disturbance, and enhance surveying effectiveness.

Implications.Increasing surveying efficiency can improve the accuracy of targeted conservation decisions.

Context. Predictive modelling of the impacts of climate change has highlighted a need for on-ground monitoring of mammal communities within the Wet Tropics bioregion of Queensland to inform wildlife conservation management. Standard mammal-survey techniques are labour intensive and often incapable of detecting rare, trap-shy or otherwise elusive species, effectively rendering them invisible to researchers even when substantial resources are applied.

Aims. To assess the utility of feeding remains (regurgitated pellets) from lesser sooty owls, Tyto tenebricosa multipunctata, for monitoring populations of small to medium-sized mammals within the Wet Tropics.

Methods. Three female lesser sooty owls were radio-tracked to determine home-range areas. Radio-tracking and targeted systematic searches were used to locate diurnal roosts containing owl pellets from which prey species were identified. Owl-pellet data were directly compared with live-trap data within three putative owl home ranges. Additionally, analyses of a dataset spanning more than 15 years demonstrated the utility of owl-pellet data for monitoring mammal communities.

Key results. Owl-pellet surveys yielded 14 mammal species (840 individuals) from 152 man-hours, compared with six mammal species (361 individuals) from 194 man-hours of live trapping. Both survey methods identified Rattus fuscipes, Melomys spp. and Antechinus spp. as the most abundant species but live-trap data were found to under-represent relative abundance of Melomys spp. and over-represent relative abundance of R. fuscipes in comparison to owl-pellet data.

Conclusions. Analysis of lesser sooty owl pellets is a particularly useful method for compilation of species inventories of small to medium-sized mammals, being more effective than standard live-trapping surveys within the rainforests of the Wet Tropics.

Implications. Owl-pellet analysis is well suited for monitoring mammal communities, as long as periodic data are collected from the same roost(s) and the pellets have been deposited by the same individual bird(s). Additional research relating to variability in behavioural traits between individual lesser sooty owls that have potential to confound results via sampling bias must be undertaken before owl-pellet data can be used for comparison of mammal community structure among sites, or for monitoring a site over a period spanning a change in the individual owls that are depositing pellets at that site.

Context. The timing and synchrony of births are important components of fitness among ungulates living in seasonal environments.

Aims. We investigated the effects of rainfall variation on interannual variation in the timing, synchrony and prolificity of births for six African ungulate species inhabiting an equatorial savanna with bimodal rainfall.

Methods. We analyse how seasonally and aseasonally breeding African savanna ungulates maintain reproductive success despite rainfall constraints, and adjust the phenology, synchrony and fecundity of their breeding to track interannual variation in rainfall. We use data on six ungulate species inhabiting the Masai Mara National Reserve (Mara) of Kenya to test five hypotheses concerning the influences of seasonality in resources, gestation length and the hider–follower strategy on the timing, synchrony and prolificity of calving.

Key results. Births were more synchronised for topi, warthog and zebra than for hartebeest, impala, and giraffe. Births occurred in most months, but tended to peak during the early rains when forage quality peaks for all species. The rainfall component exerting the strongest influence on timing of births varied with species. Gestation length, the hider–follower dichotomy, and hence predation, had apparently weak influences on birth synchrony. In drought years with nutritionally deficient forage, births were delayed, less synchronised and fewer. This portrayed protracted calving seasons, suppression of early conceptions, and delayed onset of births, calf losses, reproductive pauses or failures. However, in rainy years with sufficient forage, births peaked early, or were not delayed, and the synchronicity of calving increased for all species. This suggested early breeding by primiparous females; or higher fertility early in the mating period. The prolificity of calving increased with rainfall for topi and warthog but decreased for the remaining species.

Conclusions. Marked interannual variability in rainfall, plant phenology and forage sufficiency in tropical savannas impose strong constraints on ungulates, favouring flexible timing of births over strictly seasonal reproduction characteristic of temperate latitudes with predictable seasonal resource cues.

Implications. Despite high flexibility in their timing of births, widening rainfall variability expected to result from global warming could lower reproductive success of tropical ungulates by lowering their fecundity and survival prospects of their calves if droughts became more frequent and severe.