Context. Conservation efforts for New Zealand freshwater mussels (kākahi) are challenging because of their longevity and their complex life history, but also by the scarcity of research that has investigated causes of decline. Reproductive constraints may impair recruitment, but other key aspects that influence population structure, such as predation pressure, remain unknown. Predation is an emerging risk for kākahi because, although bivalve predation has been observed in New Zealand waterways, its prevalence and impacts remain unquantified.

Aims. The present study resolves trophic interactions with predator populations by identifying kākahi predators and examining characteristics of freshwater mussels (e.g. species or size) that may indicate vulnerability to predation.

Methods. Intensive monitoring was conducted over 6 weeks (January to March 2020) by using trail cameras to observe kākahi predators at the Orongo Stream, a western Waikato (New Zealand) site with high densities of Echyridella aucklandica (threat status: Vulnerable) and E. menziesii (Declining). Predated kākahi shell remains were analysed to (i) identify typical patterns of shell damage, and (ii) determine prey selectivity via size distribution.

Key results. Eight observations of an avian predator (pūkeko, Porphyrio porphyrio melanotus) interacting with both E. aucklandica and E. menziesii were recorded; however, E. menziesii comprised a significantly greater proportion of the shell remains that had direct evidence of predation. Both species of mussel displayed significantly more damage to the posterior end of the valves but size selectivity was detected only for E. menziesii.

Conclusions. Pūkeko actively search for mussels and frequently consume them as part of a wider diet when they are accessible during summer. Whereas healthy populations of freshwater mussels may withstand predation by native species, populations that face substantial pressure from other natural stressors and anthropogenic change may suffer. Predation impacts on kākahi populations should be a factor considered for the future management of New Zealand mussel species.

Implications. Identifying pūkeko as kākahi predators clarifies food webs for conservation managers and highlights the need to quantify their impact on mussel populations; particularly for E. menziesii, which may be more vulnerable to predation.

Context. Increasingly, ecological studies of sea turtles are measuring locomotion performance of newly emerged hatchlings in raceways and swimways under the assumption that locomotion performance measured in these structures reflects locomotion performance in nature, and that such measurements reflect the chance of a hatchling surviving dispersion from their natal beach.

Aims. The aim was to test the assumption that an individual hatchling’s performance measured in artificial structures is correlated with the same individual’s performance in the natural environment (beach and sea), adding confidence that such measurements are an indirect indicator of dispersal ability during the first 24 h of post-nest life.

Methods. Green turtle (Chelonia mydas) hatchlings that had just emerged from their nest had their crawling and swimming speeds measured in an on-beach raceway and swimway. The same hatchlings then had their beach crawling and sea swimming speed measured and the correlation between their performance in the artificial structures and natural crawls and swims calculated.

Key results. An individual sea turtle hatchling’s locomotion performance in nature was correlated with its locomotion performance in raceways and swimways, but beach crawling was generally slower than raceway crawling, and sea swimming was generally faster than swimway swimming. We also found a weaker correlation between the raceway and beach crawling speeds than the sea and swimway swimming speeds.

Conclusions. The measurement of sea turtle hatchling crawling speed and swimming speed in artificial structures correlated with the individual’s locomotion performance in nature, supporting the assumption that the locomotion performance measured in artificial structures reflects their relative locomotion performance in the natural environment.

Implications. The measurement of sea turtle hatchlings locomotion performance in artificial structures can be used to indicate how variations in the nest microenvironment such as temperature and moisture affect a hatchling’s real-life locomotion performance, and thus reflect a hatchling’s dispersal ability during the first 24 h of post-nest life. Thus, sea turtle rookery managers can use this information to assess how their incubation management strategies affect hatchling locomotion performance, and consequently their likely offshore dispersal ability.

Context. Accidental poisoning of domestic dogs is a potential risk when using baits to control invasive animals. We developed and trialled an electrical device attached to a non-toxic bait to assess whether we could induce a learned aversion towards baits in conservation-working dogs.

Aims. We tested the device on conservation-working dogs licenced to enter conservation estate as part of feral pig control, and consequently are potentially exposed to lethal baits for controlling red foxes.

Methods. Over 1 year (up to seven separate training sessions per dog), 27 dogs were sequentially presented with electrified and non-electrified non-toxic baits and their behavioural responses were recorded. On-farm training (Days 0, 1, 7, Months 1, 12) comprised dogs being called by their owner standing nearby the electrified bait. If the dog touched the bait and demonstrated aversive behaviour (we assume that it received an electric shock or ‘correction’), it was then presented with a non-electrified bait. If they ate either bait, they were shown another electrified bait (up to three electrified baits per session).

Key results. Seventeen dogs (17/27) touched the bait and received a correction. Eleven dogs required only a single correction and did not touch another bait, three dogs needed two corrections, and two dogs needed three or four corrections. These 17 dogs showed increasing avoidance to the bait over successive training sessions (χ²₁₂ = 67.96, P < 0.001), including avoiding looking at the bait, refusing to come within 5–10 m of the bait and their owner, or leaving the training vicinity. All these dogs (17/17) avoided baits encountered in a working environment (1/17 touched but did not consume a bait) and bait-aversion was still detected up to 1-year post-initial training. Nine dogs (9/27) did not appear to receive a correction or show any change in bait-aversion behaviour. One dog (1/27) showed no aversion to the stimulus and continued to eat baits.

Conclusions. Here we present a proof of concept for a deterrent device and associated experimental protocol to produce learned aversion behaviour in conservation-working dogs.

Implications. We demonstrated that it is possible to induce a learned aversion to baits in conservation-working dogs, thereby reducing the risk of accidental poisoning.

Context. Wild dogs are a significant pest species of livestock production and native wildlife in Australia. A suite of control tools is used to mitigate predation impacts. Baiting with sodium fluoroacetate is the most commonly used control tool in Australia; however, its effectiveness can be reduced by interference by non-target species, and in some contexts by microbial degradation of the toxin. Canid pest ejectors (CPEs) are a mechanical device with an attractant ‘lure head’ designed to eject a lethal toxin into the mouth of canids pulling on the lure head. A range of lure heads can be used to attract canids to pull, and trigger CPEs.

Aims. We aimed to determine whether uptake of CPEs by wild dogs in an arid rangeland environment could cause a decline in a wild dog population. We also aimed to determine whether there are particular lure heads that increase the rate of CPEs being triggered by wild dogs.

Methods. We deployed one hundred CPEs over four sessions of control across three properties in the southern rangelands of Western Australia from 2018 to 2020. Each session consisted of 2 months of CPE deployment with two different lure heads, totalling eight lure head types over the entire study. All CPEs were monitored using camera traps.

Key results. Wild dog density varied over the study period. In all four control sessions, a decrease in wild dog density was recorded (–46%, –5%, –13%, –38%). Wild dog activity events on camera and their interest in CPEs differed between sessions and lures (i.e. higher with scent-based lures). Non-target species did not interfere with CPEs significantly, despite a higher number of activity events by non-target species than wild dogs.

Conclusions. CPEs caused a reduction of 5–46% of wild dog density when deployed in the southern rangelands of Western Australia. Non-target interference was minimal when using CPEs for wild dog control.

Implications. Use of scent-based lures on felt lure heads is recommended for successful use of CPEs for wild dog control in arid rangeland environments. Future on-ground wild dog control should include CPEs as a complementary tool for the reduction of wild dog density.

Context. Rangelands can play an important role in conservation by providing additional habitat for many threatened species and maintaining global biodiversity. Identifying areas that can integrate both pastoral and conservation activities is important for capturing benefits from wildlife in non-protected areas.

Aims. To investigate wildlife distribution in a contiguous landscape comprising both pastoral ranches and wildlife-based areas in western Botswana.

Methods. We deployed motion-activated camera traps to assess mammal richness and occupancy using a multi-species occupancy model. We tested whether environmental factors influenced these parameters in a commercial ranching block in the western Kalahari region of Botswana, and whether species-specific occupancy varied between ranches and neighbouring wildlife management areas.

Key results. In the ranching block, vegetation, season and distance to wildlife areas influenced species-specific occupancy and species richness, whereas farm type and water availability affected only a few carnivore species. Commercial ranches supported several threatened species such as African wild dog, cheetah and pangolin, and we detected two species, African civet and serval, not previously considered being present in this region. Mammal diversity was similar between ranches and wildlife areas, but species composition varied. Land use affected species-specific occupancy, with many carnivore species occurring close to or in wildlife areas.

Conclusions. We showed that commercial ranches in the Kalahari are utilised by many mammal species, and these areas may play an important role in the conservation of threatened species. Understanding species-, group- and community-level responses to the impacts of human activities in rangelands is vital as the need for pastoral land increases.

Implications. We predicted regions of high occurrence of carnivores that can be important for tackling human–wildlife conflict as well as regions with high species diversity that may be useful for increasing integration of conservation endeavours (e.g. eco-tourism) that promote the benefits of wildlife in predominantly livestock regions.

Context. The ability to accurately estimate age of animals is important for both research and management. The two methods for age estimation in ungulates are tooth replacement and wear (TRW) and cementum annuli (CA). Errors in estimated TRW ages are commonly attributed to environmental conditions; however, the influence of environmental variables on tooth wear has not been quantified. Further, the performance of CA in environments with weak seasonality has not been thoroughly evaluated.

Aims. The study had the following three goals: identify environmental and morphological factors that influenced estimated ages, quantify accuracy of TRW and CA, and develop TRW ageing criteria that minimise error.

Methods. We used data from harvested (n = 5117) and free-ranging, known-age white-tailed deer (n = 134) collected in southern Texas, USA, to quantify environmental and morphological influences on estimated TRW ages, and assess biases in both methods.

Key results. We observed substantial variation in age estimates for both TRW and CA. Soil, drought and supplemental nutrition had minor effects on tooth wear, insufficient to alter age estimates by ≥1 year. Body mass and antler size influenced age estimates for TRW only for extreme outliers. Both methods were biased and tended to under-estimate ages of adult deer, especially TRW. Wear on the first molar was most correlated with the known age (r² = 0.78) and allowed biologists to correctly place known-age deer into age classes of 2, 3–5, and ≥6 years old 72%, 73% and 68% of the time, an improvement compared with the 79%, 48% and 28% accuracy from pooled TRW.

Conclusions. We observed substantial inter- and intra-individual variation in tooth-wear patterns that became more pronounced in older deer. Individual variation had a greater influence on TRW ages than did environmental covariates, whereas CA ages appeared unaffected by environment. Although variable, age estimates were ±1 year of the true age 87% and 93% of the time for TRW and CA respectively.

Implications. Managers, ecologists and epidemiologists often incorporate ages into population models. The high inter-individual variation in estimated ages, the tendency to underestimate ages of older deer, and the ageing method need to be considered.

Context. Climate and land use are among the most important drivers of global biodiversity change, and they may be operating at different spatial scales. The effects of cross-scale interactions (CSIs) between these drivers on avian abundance are poorly understood.

Aims. Our primary objective was to assess whether the abundances of eight forest bird species in the eastern United States were significantly associated with CSIs involving four subregional climate variables (breeding- and pre-breeding-season temperature and precipitation) and two landscape variables (percentage exurban cover and forest patch size).

Methods. For North American Breeding Bird Survey routes in six U.S. Environmental Protection Agency Level II ecoregions, we measured subregional climate variables within species maximum natal dispersal distances, and we measured landscape variables within species median natal dispersal distances. Using Akaike’s information criterion and negative-binomial regression, we compared the fits of 21 a priori competing models separately for each of the eight species, and separately for percentage exurban cover and forest patch size (8 × 2 = 16 model sets).

Key results. Total abundances during 2009–2013 of all eight species were associated with CSIs, which were informative in nine of the 16 best-supported models. The informative CSIs in the best-supported models involved all four subregional climate and both landscape variables. These results were evident after we accounted analytically for various methodological and environmental covariates, including within-scale interactions, that may otherwise have obscured the effects of CSIs. In some models, CSIs were more influential than were the associated additive effects, similar within-scale interactions, or other environmental variables, whereas in other models they were not. The associations between species abundances and CSIs were species-specific.

Conclusions. CSIs among global drivers of change may be common, and failure to identify CSI effects may result in misleading bird−landscape models.

Implications. Understanding how CSIs modify the effects of variables at different spatial scales may be crucial for effective broad-scale management of declining species. Conservation attention to species that are presently common but declining in abundance may help avoid extirpation in parts of their geographic ranges.

Context. Reliable, cost-effective monitoring methods are essential for managing wildlife populations. Scat-and-sign surveys (i.e. monitoring defecation, animal scratching, footprints, food remains) are a rapid, low-cost, non-invasive monitoring approach, but unquantified biases and uncertainties associated with these methods have caused researchers to doubt their reliability.

Aims. We sought to quantify how richness, occupancy and activity estimates derived from a long-term camera-trap study differed from those of scat surveys in the same locations, to determine scat-survey reliability and model bias corrections.

Methods. We used transect-based scat surveys at 110 sites in the temperate forests of southern Tasmania (Australia), to estimate occupancy, activity and community richness for common, ground-dwelling vertebrates. These results were compared with estimates derived from a long-term passive camera-trap study at the same sites. In addition, time-lapse imagery taken with the camera traps was used to monitor the persistence of rufous-belled pademelon (Thylogale billardierii) and Tasmanian devil (Sarcophilus harrisii) scats in relation to environmental correlates.

Key results. Scat persistence differed between these two species. The half-life of S. harrisii scats was 113 days, compared with 63 days for T. billardierii. Generalised linear modelling showed that scat surveys were most efficacious at sites with little disturbance and homogenous substrates. Overall, scat surveys consistently underestimated site occupancy and richness relative to the camera traps (μ = 2.7:1), but this bias was inconsistent, with the ratio exceeding 15 for the arboreal brushtail possum (Trichosurus vulpecula). Scats were most reliably detected for large, trail-using mammals such as S. harrisii, T. billardierii, and common wombat (Vombatus ursinus). Scat surveys were less useful for the surveillance of low-density and arboreal species. Scats were uncommon for the two bird species examined, but alternative superb lyrebird (Menura novaehollandiae) signs were detected reliably.

Conclusions. Scat surveys reliably detected large, trail-using mammals. However, estimates of activity were poorly correlated between camera traps and scat surveys.

Implications. When used appropriately, scat surveys can provide an effective and cheap ‘snapshot’ index for wildlife monitoring, especially if the species-specific biases have been calibrated for the vertebrate community and environment under monitoring.

Context. Helicopter-based shooting has been widely used to kill deer in Australasia, but the animal welfare outcomes of this technique have not been evaluated.

Aim. To assess the animal welfare outcomes of helicopter-based shooting of deer in Australia by quantifying the fates of deer seen and shot at, the duration of procedures and the number and location of bullet wounds in deer.

Methods. Three deer control operations were assessed. These operations targeted: (1) chital deer (Axis axis) in Queensland, (2) fallow deer (Dama dama) in Australian Capital Territory and (3) fallow deer in New South Wales. For each operation, an independent veterinarian conducted ante-mortem (i.e. from the helicopter as shooting occurred) and post-mortem (i.e. from the ground after shooting had ceased) observations. The ante-mortem data were used to estimate the proportion of deer seen that were shot, chase time (CT), time to insensibility (TTI) and total time (TT; CT + TTI). The numbers and locations of bullet wounds were recorded post-mortem.

Key results. Ante-mortem and post-mortem observations were performed for 114–318 and 60–105 deer, respectively, in the three operations. Shots were fired at 69–76% of deer that were observed. Median CT ranged from 73 to 145 s. Median TTI ranged from 17 to 37 s and median TT ranged from 109 to 162 s. The mean number of bullet wounds per deer ranged from 1.43 to 2.57. Animal welfare outcomes were better in the two fallow deer operations than in the chital deer operation. In both fallow deer operations, most deer were shot multiple times and at least once in the head or thorax. In contrast, chital deer were shot fewer times and less often in the head or thorax, and non-fatal wounding was observed.

Conclusions. The best animal welfare outcomes were achieved when helicopter-based shooting operations followed a fly-back procedure and mandated that multiple shots were fired into each animal.

Implications. Animal welfare outcomes for helicopter-based deer shooting in Australia could be improved with a national-level standard operating procedure requiring helicopters to fly back over shot animals and repeatedly shoot animals in the head or thorax.

Context. Camera trapping is increasingly used to collect information on wildlife occurrence and behaviour remotely. Not only does the technique provide insights into habitat use by species of interest, it also gathers information on non-target species.

Aims. We implemented ground-based camera trapping to investigate the behaviours of ground-dwelling birds, a technique that has largely been unutilised for studying birds, especially in wind-energy facilities.

Methods. We used camera traps to monitor activities of Agassiz’s desert tortoises (Gopherus agassizii) at their self-constructed burrows in a wind-energy facility near Palm Springs, California, USA. While doing so, we collected data on numerous burrow commensals, including birds.

Key results. Monitoring from late spring to mid-autumn in one year showed regular use of tortoise burrows and the immediate area by 12 species of birds, especially passerines. The most abundant species, as indicated by the number of photographs, but not necessarily individuals, was the rock wren (Salpinctes obsoletus), with a total of 1499 events. Birds appeared to use the interior or proximate vicinity of burrows for gathering nesting material, displaying, feeding, dust bathing and other activities. Of the bird species observed, 10 are known to be occasional casualties of turbine-blade strikes. The minimum known-age of a burrow had a positive relationship with bird counts.

Conclusions. Using camera traps focused at ground level can be a useful tool in avian conservation efforts because it is an effective technique for measuring bird presence, activity and behaviour in altered habitats such as wind farms, especially for those species that are low flyers or ground dwellers.

Implications. Acquiring data over the long term by using ground-based monitoring with camera traps could add to our understanding of avian behaviour and habitat use in relation to wind-energy infrastructure and operations, and help determine the vulnerability of avifauna that utilise the area.