Health and environmental effects to wildlife from radio telemetry and tracking devices-state of the science and best management practices

This paper discusses the potential health risks and benefits to tagged wildlife from the use of radio tracking, radio telemetry, and related microchip and data-logger technologies used to study, monitor and track mostly wildlife in their native habitats. Domestic pets, especially canids, are briefly discussed as radio-tagging devices are also used on/in them. Radio tracking uses very high frequency (VHF), ultra-high frequency (UHF), and global positioning system (GPS) technologies, including via satellites where platform terminal transmitters (PTTs) are used, as well as geo-locating capabilities using satellites, radio-frequency identification (RFID) chips, and passive integrated responder (PIT) tags, among others. Such tracking technologies have resulted in cutting-edge findings worldwide that have served to protect and better understand the behaviors of myriad wildlife species. As a result, scientists, field researchers, technicians, fish and wildlife biologists and managers, plus wildlife and other veterinarian specialists, frequently opt for its use without fully understanding the ramifications to target species and their behaviors. These include negative physiological effects from electromagnetic fields (EMF) to which many nonhuman species are exquisitely sensitive, as well as direct placement/use-attachment impacts from radio collars, transmitters, and implants themselves. This paper provides pertinent studies, suggests best management practices, and compares technologies currently available to those considering and/or using such technologies. The primary focus is on the health and environmental risk/benefit decisions that should come into play, including ethical considerations, along with recommendations for more caution in the wildlife and veterinarian communities before such technologies are used in the first place.

A practical approach with drones, smartphone and tracking tags for potential real-time tracking animal

In recent years, drones are increasingly used for fauna monitoring and wildlife tracking; however, the application of drones for tracking wildlife is restricted to those users with the technical capacity to develop such systems. We explore the potential of wildlife tracking with drones by using a system consisting of a multirotor drone, smartphones, and commercial tracking devices via Bluetooth and Ultra-Wide Band (UWB) off-the-shelf that is easy to use by non-specialists. We present the system configuration, explore the operational parameters that can affect detection capabilities, and test the effectiveness of the system in locating targets by simulating target animals in savanna and forest environments. The self-contained tracking system was built without the need for hardware or software customization. From 40 tracking flights carried out in the Cerrado biome, we obtained a detection rate of 90% in savanna and 40% in forest areas. Considering the moving tests (N = 20) the detection rates were 90% in the savanna and 30% in the forest areas. The spatial accuracy obtained by the system was 14.61 m, being significantly more accurate in savanna areas (x̄ = 10.53) than in forest areas (x̄ = 13.06). This approach to wildlife tracking facilitates the use of drones by non-specialists and at an affordable cost for conservation projects with limited resources. The reduced size of the tags, the long battery life and the reduced cost in relation to GPS-tags opens up a range of opportunities for tracking small to large fauna present in this type of vegetation.

A pain in the neck: weak links are not a reliable release mechanism for radio-collars

Collars are an attachment method commonly used to mount data collection devices on wildlife. Removal of collars at the completion of a data collection period is a high priority for the purpose of animal welfare, but retrieval of collars can often be difficult. Weak links or other drop-off devices are used by researchers with the intention of improving collar retrieval rates, and for mitigation of animal welfare risks associated with collar entanglement. However, the design and effectiveness of such devices is not regularly reported in detail in the literature. We surveyed wildlife researchers to collate and communicate their experiences with weak links, and assess their attitudes towards collaring Australian mammals in the 35–5500 g weight range. Forty-five researchers responded to the survey, of whom 25 had used weak links in at least one study. There was very little consistency between the performances of weak links, with researchers finding them effective in less than half of the scenarios reported upon. Outcomes varied depending on the type of material used for the link, the species being collared, and the environmental conditions under which the collars were being deployed. We recommend (1) researchers test weak links prior to deployment; (2) users to not rely upon weak links as the primary method of collar retrieval; and (3) continued communication of design and outcomes of all radio-collars deployed including those with weak links.

Long-Distance Movements of Feral Cats in Semi-Arid South Australia and Implications for Conservation Management

Simple Summary

To efficiently control invasive animals, it is vital to have knowledge about their behaviour, their movements and how they use the landscape. Unusual behaviour is normally excluded from datasets, as it is considered to be an outlier that may distort analyses. In our study, we present movement data from feral cats in the arid and semi-arid zones of Australia. Feral cats are a serious problem to the native wildlife of Australia and in many parts of the world. Cats are known to show fidelity to geographic areas and may defend them against other cats. Until now, research has focused on these areas, home ranges or territories, that feral cats need to survive and reproduce. We argue that a part of their movement behaviour, large journeys away from the area they normally use, has been overlooked and has been considered to be unusual behaviour. We explain why we think that this is the case and present examples from other studies additional to our data set to show that these long-distance movements are a regular occurrence. To achieve a better protection of native wildlife from predation by feral cats, we believe that these long-distance movements should be considered as part of the normal behaviour of feral cats when planning cat control operations.

Abstract

Movements that extend beyond the usual space use of an animal have been documented in a range of species and are particularly prevalent in arid areas. We present long-distance movement data on five feral cats (Felis catus) GPS/VHF-collared during two different research projects in arid and semi-arid Australia. We compare these movements with data from other feral cat studies. Over a study period of three months in the Ikara-Flinders Ranges National Park, 4 out of 19 collared cats moved to sites that were 31, 41, 53 and 86 km away. Three of the cats were males, one female; their weight was between 2.1 and 4.1 kg. Two of the cats returned to the area of capture after three and six weeks. During the other study at Arid Recovery, one collared male cat (2.5 kg) was relocated after two years at a distance of 369 km from the area of collar deployment to the relocation area. The movements occurred following three years of record low rainfall. Our results build on the knowledge base of long-distance movements of feral cats reported at arid study sites and support the assertion that landscape-scale cat control programs in arid and semi-arid areas need to be of a sufficiently large scale to avoid rapid reinvasion and to effectively reduce cat density. Locally, cat control strategies need to be adjusted to improve coverage of areas highly used by cats to increase the efficiency of control operations.

Application of low-power wide-area network GPS to koala monitoring

We evaluated long range antennae and associated solar-powered global positioning system (GPS) ear tags designed for use with domestic cattle, as a novel system for monitoring ranging behaviour of the koala (Phascolarctos cinereus). The mean location error of our GPS tags was 33.9 m (s.e. = 0.46). The tags were relatively light (30 g), reported eight locations per day when attached to koala radio-collars and had an operating life that exceeded our study period (8 months). Deployed as a stand-alone, solar powered, remote system, this technology can provide a viable option for wildlife tracking projects.

Potential effects of GPS collars on the behaviour of two red pandas (Ailurus fulgens) in Rotterdam Zoo

GPS collars are frequently used to study the (behavioural) ecology of species. However, such collars can cause behavioural changes and can have negative physiological effects on the individuals wearing them. A pilot study to obtain data on behavioural and physiological effects of GPS collars on the target species would therefore be recommended, especially when it concerns rare or endangered species. The red panda (Ailurus fulgens) is a small carnivore endemic to the mountains of Central Asia that is currently classified as endangered. There is a lack in knowledge on the species ecology which could be enhanced by a study using GPS-technology. As a pilot study, the two adult red pandas in Rotterdam Zoo were observed before and after fitting a GPS-collar, to determine possible behavioural effects of wearing a collar. Although the study did not take place under ideal circumstances, indications of both behavioural, e.g. increased shaking behaviour, and physical, e.g. abrasions, effects of the collar were found. Even though our results were only based on two individuals, our findings stress the need for pilot studies in controlled environments before GPS collars to ensure safety of the study species and validity of the collected data.

Translocation is not a viable conflict-resolution tool for a large fossorial mammal, Lasiorhinus latifrons

Abstract ContextThe translocation of southern hairy-nosed wombats (Lasiorhinus latifrons) has been suggested as a management tool to alleviate conflicts with the agricultural sector because of the damages caused by their burrowing activity. Translocation is widely used for removing problem animals from conflict areas, but its effectiveness is rarely adequately evaluated and often fails to resolve conflicts. Furthermore, translocations often result in low survival, extensive movement, and the non-establishment of translocated animals. AimsThe present study assessed the viability of translocation as a damage-mitigation tool for L. latifrons, by examining the (1) capture success of L. latifrons, (2) survival and establishment of translocated L. latifrons, and (3) reduction of L. latifrons activity at source sites. MethodsThirteen L. latifrons individuals were translocated from conflict zones on agricultural properties and released on a private grazing property >60km from capture sites. The behaviour of translocated L. latifrons individuals was monitored using GPS and/or VHF technology, and compared with that of 12 resident animals. Motion-sensor cameras monitored the source sites to determine recolonisation rates. Key resultsThe capture and removal of problem individuals were time-intensive and infeasible on a large scale. Post-release mortality was not observed, although nine translocated and nine resident L. latifrons individuals went missing soon after release. Translocated (n=4) L. latifrons displayed high site fidelity, but initially ranged further than residents (n=6), before settling into similar behaviour patterns. Lasiorhinus latifrons activity was not reduced at the source sites, with neighbouring wombats recolonising warrens within 1–2 weeks. ConclusionsTranslocation is not a suitable human–wombat conflict mitigation tool but may prove useful for restoring declining populations. ImplicationsThese findings support the growing body of evidence that translocating problem animals is not suitable for resolving conflicts and alternative methods such as the use of deterrents may be more appropriate.

Spatial ecology of an endangered carnivore, the Pilbara northern quoll

Understanding the spatial requirements of a species allows one to tailor actions that can help protect species and their habitats. We investigated the spatial needs of the endangered northern quoll (Dasyurus hallucatus) in the Pilbara. We analysed field data based on GPS-telemetry or a combination of GPS and VHF telemetry for 11 northern quolls with data collected over two week periods. Using MCP and Kernel methods, we found average short-term ranges of 193ha and 115ha for males, and for the only female with reliable data the estimates were 34ha and 23ha, respectively, with Kernel-based core areas that were between five and three times smaller for males and the female, respectively. We found support for our hypothesis that ranges differ between seasons, but with a seasonal trend that was different from that expected. The ranges of males during the premating/mating season were smaller than during the pouch-young season. Our study provides the first detailed attempt to define and understand short-term movement behaviour of the Pilbara northern quoll. The information derived from our study can help to increase the accuracy of predictive outputs and better inform habitat prioritisation and conservation management of the Pilbara northern quoll population.

A trial of transmitter attachment methods for Shark Bay bandicoots (Perameles bougainville)

In mammal reintroductions, effective post-release monitoring often relies on the use of radio-transmitters. Collars are a popular attachment technique but are not necessarily appropriate for all taxa. However, other attachment methods may result in substantially reduced monitoring durations. We assessed several transmitter types for the Shark Bay bandicoot (Perameles bougainville), aiming to optimise animal welfare and attachment duration. Collars (fitted under general anaesthetic) were considered the optimal method and 12 bandicoots were collared and monitored as part of a reintroduction program. We found that our collars permitted monitoring for up to seven weeks, while causing minimal harm to the animals.

Post-Release Monitoring of Western Grey Kangaroos (Macropus fuliginosus) Relocated from an Urban Development Site

Simple Summary

As a result of urban development, 122 western grey kangaroos (Macropus fuliginosus) were relocated from the outskirts of Perth, Western Australia, to a nearby forest. Tracking collars were fitted to 67 of the kangaroos to monitor survival rates and movement patterns over 12 months. Spotlighting and camera traps were used as a secondary monitoring technique particularly for those kangaroos without collars. The survival rate of kangaroos was poor, with an estimated 80% dying within the first month following relocation and only six collared kangaroos surviving for up to 12 months. This result implicates stress associated with the capture, handling, and transport of animals as the likely cause. The unexpected rapid rate of mortality emphasises the importance of minimising stress when undertaking animal relocations.

Abstract

The expansion of urban areas and associated clearing of habitat can have severe consequences for native wildlife. One option for managing wildlife in these situations is to relocate them. While there is a general perception that relocation is humane, transparency of outcomes is lacking. Here, we document the outcome of 122 western grey kangaroos (Macropus fuliginosus) relocated from an urban development site on the edge of Perth, Western Australia. Global Positioning System (GPS) or Very High Frequency (VHF) collars were fitted to 67 kangaroos, and their survival and movement were monitored over 12 months using telemetry, camera traps and spotlighting. Only six collared animals survived for the duration of the study with most dying within a week of the relocation, indicating stress associated with capture as the likely cause. By the completion of the study, 111 kangaroos were predicted to have died based on the proportion of individuals known to have died. Movement patterns of surviving GPS collared kangaroos changed over time from largely exploratory forays, to more repeated movements between focus areas within home ranges. The poor outcome here raises concerns around the viability of relocating a relatively large number of kangaroos as a management option. It also highlights the need for careful planning to limit the stress associated with capture and transport if relocations are to be used for managing kangaroos in urban areas.

Efficacy of Management and Monitoring Methods to Prevent Post-Harvest Losses Caused by Rodents

The presence of pest rodents around food production and storage sites is one of many underlying problems contributing to food contamination and loss, particularly influencing food and nutrition security in low-income countries. By reducing both pre- and post-harvest losses by rodents, millions of food-insecure people would benefit. As there are limited quantitative data on post-harvest rice losses due to rodents, our objectives were to assess stored rice losses in local households from eight rural communities and two rice milling factories in Bangladesh and to monitor the effect of different rodent control strategies to limit potential losses. Four treatments were applied in 2016 and 2017, (i) untreated control, (ii) use of domestic cats, (iii) use of rodenticides, (iv) use of snap-traps. In total, over a two-year period, 210 rodents were captured from inside people's homes, with Rattus rattus trapped most often (n = 91), followed by Mus musculus (n = 75) and Bandicota bengalensis (n = 26). In the milling stations, 68 rodents were trapped, of which 21 were M. musculus, 19 R. rattus, 17 B. bengalensis, 8 Rattus exulans, and 3 Mus terricolor. In 2016, losses from standardised baskets of rice within households were between 13.6% and 16.7%. In 2017, the losses were lower, ranging from 0.6% to 2.2%. Daily rodent removal by trapping proved to be most effective to diminish stored produce loss. The effectiveness of domestic cats was limited.

Review of GPS collar deployments and performance on nonhuman primates

Over the past 20 years, GPS collars have emerged as powerful tools for the study of nonhuman primate (hereafter, "primate") movement ecology. As the size and cost of GPS collars have decreased and performance has improved, it is timely to review the use and success of GPS collar deployments on primates to date. Here we compile data on deployments and performance of GPS collars by brand and examine how these relate to characteristics of the primate species and field contexts in which they were deployed. The compiled results of 179 GPS collar deployments across 17 species by 16 research teams show these technologies can provide advantages, particularly in adding to the quality, quantity, and temporal span of data collection. However, aspects of this technology still require substantial improvement in order to make deployment on many primate species pragmatic economically. In particular, current limitations regarding battery lifespan relative to collar weight, the efficacy of remote drop-off mechanisms, and the ability to remotely retrieve data need to be addressed before the technology is likely to be widely adopted. Moreover, despite the increasing utility of GPS collars in the field, they remain substantially more expensive than VHF collars and tracking via handheld GPS units, and cost considerations of GPS collars may limit sample sizes and thereby the strength of inferences. Still, the overall high quality and quantity of data obtained, combined with the reduced need for on-the-ground tracking by field personnel, may help defray the high equipment cost. We argue that primatologists armed with the information in this review have much to gain from the recent, substantial improvements in GPS collar technology.

Conserving Australia’s threatened native mammals in predator-invaded, fire-prone landscapes

Abstract Inappropriate fire regimes and predation by introduced species each pose a major threat to Australia’s native mammals. They also potentially interact, an issue that is likely to be contributing to the ongoing collapse of native mammal communities across Australia. In the present review, I first describe the mechanisms through which fire could create predation pinch points, exacerbating the impacts of predators, including red foxes, Vulpes vulpes, and feral cats, Felis catus, on their native mammalian prey. These mechanisms include a localised increase in predator activity (a numerically mediated pathway) and higher predator hunting success after fire (a functionally moderated pathway), which could both increase native mammal mortality and limit population recovery in fire-affected landscapes. Evidence for such interactions is growing, although largely based on unreplicated experiments. Improving native mammal resilience to fire in predator-invaded landscapes requires addressing two key questions: how can the impacts of introduced predators on native mammals in fire-affected areas be reduced; and, does a reduction in predation by introduced species result in higher native mammal survival and population recovery after fire? I then examine potential management options for reducing predator impacts post-fire. The most feasible are landscape-scale predator control and the manipulation of fire regimes to create patchy fire scars. However, robust field experiments with adequate statistical power are required to assess the effectiveness of these approaches and preclude null (e.g. compensatory mortality) or adverse (e.g. mesopredator or competitor release) outcomes. Ongoing predator management and prescribed burning programs provide an opportunity to learn through replicated natural experiments as well as experimental manipulations. Standardised reporting protocols and cross-jurisdiction monitoring programs would help achieve necessary spatial and environmental replication, while multi-trophic, spatially explicit simulation models could help synthesise findings from disparate study designs, predict management outcomes and generate new hypotheses. Such approaches will be key to improving management of the complex mechanisms that drive threatened native mammal populations in Australia’s predator-invaded, fire-prone landscapes.

Scattered paddock trees and roadside vegetation can provide important habitat for koalas (Phascolarctos cinereus) in an agricultural landscape

Habitat loss and fragmentation threaten the survival of koalas in Queensland. In rural landscapes, remaining koala habitat is often in the form of scattered paddock trees, patches of vegetation and roadside vegetation. The aims of this study were to (1) quantify the use of these three habitat types; (2) determine whether there is an increased use of scattered trees during the breeding season; and (3) describe the movement characteristics (daily step-length and turning angle) of koalas in different habitat types. To do this, koalas were caught and fitted with global positioning system (GPS) loggers that recorded their daily locations. We found koalas utilised all three habitat types in both breeding and non-breeding seasons, but roadside vegetation and scattered trees were utilised significantly more than expected based on their availability within the landscape. We found no significant difference in step-length or turning angles in scattered trees compared with patches of vegetation. We conclude that scattered trees are a critical element of habitat in this rural landscape. This work provides evidence that retaining or planting scattered trees within the rural landscape would likely complement or possibly enhance the conservation value of rural landscapes for koalas.

Right on track? Performance of satellite telemetry in terrestrial wildlife research

Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental factors that determine the success and failure of satellite tracking devices across species and habitats. Here, we assess the relative influence of such factors on the ability of satellite telemetry units to provide the expected amount and quality of data by analyzing data from over 3,000 devices deployed on 62 terrestrial species in 167 projects worldwide. We evaluate the success rate in obtaining GPS fixes as well as in transferring these fixes to the user and we evaluate failure rates. Average fix success and data transfer rates were high and were generally better predicted by species and unit characteristics, while environmental characteristics influenced the variability of performance. However, 48% of the unit deployments ended prematurely, half of them due to technical failure. Nonetheless, this study shows that the performance of satellite telemetry applications has shown improvements over time, and based on our findings, we provide further recommendations for both users and manufacturers.

A review of methods used to capture and restrain introduced wild deer in Australia

Six non-native deer species have established wild populations in Australia, and most are expanding in distribution and abundance. There is therefore increasing focus on the need to understand and manage these species. Capturing and immobilising wild deer is essential for many research and management applications, but the best methods for doing this have not been identified for the Australian situation. To address this knowledge gap, we systematically reviewed methods used to physically capture and chemically immobilise the six wild deer species in Australia. A variety of physical and chemical restraint methods have been used to capture wild deer in Australia, but these have seldom been reported in peer-reviewed publications. Physical capture methods have employed a variety of trapping and netting configurations. Some chemical immobilisation approaches have used oral baiting, but most have relied on darting of free-ranging animals or hand-injection of physically restrained deer. There is uncertainty about the efficacy and animal welfare impacts of the techniques currently used to capture wild deer in Australia. Improved reporting of capture outcomes would facilitate the identification of ‘best practice’ techniques for capturing wild deer in Australian environments.

Biotelemetry marches on: A cost-effective GPS device for monitoring terrestrial wildlife

The availability of low-cost wildlife trackers increases the capacity to collect valuable ecological data when research budgets are limited. We converted a commercially available global positioning system (GPS) product into a low-cost tracking device that sends data via the mobile phone network, and assessed its performance under varying conditions. We established a stationary test, deploying devices along a continuum from open urban areas to topographically and structurally complex forested sites. We tested three features of the device: (a) the GPS, by measuring fix success rate, fix precision and horizontal dilution of precision (HDOP), (b) remote download capacity via the mobile phone network and (c) battery drain. Measures of GPS performance demonstrated high fix success rates and precision. HDOP values were influenced by habitat type and topographical position, but generally remained very low, giving an acceptable degree of error for most applications in wildlife research. Devices experienced delayed data transmission at sites with less phone reception, and faster battery drain at sites with denser vegetation. We recorded device malfunctions in 8.2% of the 110 sampling locations, but these were not associated with habitat type or topography. Our device was effective under a wide range of conditions, and the development process we used provides guidance to other researchers aiming to develop cost-effective wildlife trackers. Reducing the financial and labour costs of acquiring high-quality movement data will improve the capacity to increase sample size in animal movement studies.

Using GPS Technology to Understand Spatial and Temporal Activity of Kangaroos in a Peri-Urban Environment

Simple Summary

Kangaroo–human conflict is increasing in the peri-urban communities of the New South Wales (NSW) north coast in Australia. A way to assist in managing this conflict is to improve our understanding on the ecology of kangaroos in the peri-urban environment. We utilized modern Global Positioning System (GPS) technology to track adult male kangaroo movements in a peri-urban housing estate at Coffs Harbour, Australia, using both collars and temporary glue-on devices. We also assessed the effectiveness of the glue-on devices, which do not require animal recapture for device retrieval. Kangaroos remained predominately within the residential area and moved over short distances with small movement speeds. Movement activity peaked from 6:00 a.m. to 8:00 a.m., coinciding with daily residential activities such as driving to work, putting children on the school bus, hanging out the washing, and putting bins on the street. In addition, the temporary glue-on devices were effective in gaining information on spatial and temporal activity on a day-by-day basis, despite having short deployment lengths.

Abstract

The increasing kangaroo occurrence in expanding peri-urban areas can be problematic when kangaroos become aggressive towards people and present a collision risk to motor vehicles. An improved understanding on kangaroo spatial and temporal activity patterns in the peri-urban environment is essential to manage kangaroo–human conflict. In this study, we used GPS telemetry to determine activity patterns of male Eastern Grey Kangaroos (Macropus giganteus) in a peri-urban community on the north-coast of New South Wales, Australia. Two types of GPS devices were employed; collars and cheaper alternative glue-on units. Kangaroos moved on average 2.39 km a day, with an average movement rate of 1.89 m/min, which was greatest at dawn. The GPS glue-on devices had short deployment lengths of one to 12 days. Despite limitations in attachment time, the glue-on devices were viable in obtaining daily spatial and temporal activity data. Our results aid towards alleviating conflict with kangaroos by providing new insights into kangaroo movements and activity within a peri-urban environment and introduces a potential cheap GPS alternative for obtaining this data relative to more expensive collars.

Effect of GPS sample interval and paddock size on estimates of distance travelled by grazing cattle in rangeland, Australia

The distance travelled by an animal, when determined by using global positioning system (GPS) coordinates, is usually calculated assuming linear movement between the recorded coordinates. When using long sample intervals, some movement may be overlooked if linear movement between each recorded position is assumed, because of the tendency of livestock to move in meandering paths. Conversely, overestimation of the true distance travelled could occur with short sample intervals because of the accumulation of extra distance due to GPS measurement error. Data from 10 experiments were used to explore the effect of paddock size and GPS sampling rate on the calculation of distance travelled by free-ranging cattle. Shortening the sample interval increased apparent distance travelled according to a power function. As paddock size increased from <1 ha to >450 ha, distance travelled increased according to a logarithmic relationship; however, other variation between experiments could have affected these results. It was concluded that selecting an optimal GPS sampling interval is critical to accurately determining the distance travelled by free-ranging cattle.

Urban primate ranging patterns: GPS-collar deployments for Macaca fascicularis and M. sylvanus

The global increase in urbanization is leading to heavier interface between humans and wildlife. Within these anthropogenic landscapes, little is known about ranging patterns, particularly with regard to urban primates. Here we present the results of the first long-term deployment of multiple GPS collars on two species of macaques to investigate the impacts of urbanization on urban primate ranging patterns in Singapore and Gibraltar. Collars data acquisition were excellent with respect to the amount, quality, and accuracy of data collected; however, remote connectivity and drop-off functionality was poor across all deployments. Analyses highlighted high variability in ranging patterns between individuals within each species that aligned with access to human food resources and patterns of tourism. Individuals from troops with less access to human food had much larger home, core, and day ranges relative to those with regular provisioning or raiding opportunities. Almost no temporal range overlap was observed between any focal individuals at either site and spatial overlap was low for all but two troops at each site. We found no relationship between anthropogenic schedules and changes in ranging patterns. Significant seasonal variation existed for daily path length and day range size for both the Singapore long-tailed and the Gibraltar Barbary macaques, with long-tailed macaques increasing their range during the equatorial monsoon season and Barbary macaques increasing their range during drier, summer months. This study highlights how the behavioral plasticity found within the genus Macaca is reflected in ranging pattern variability within urban environments.

An inexpensive satellite-download GPS receiver for wildlife: field trial on black swans

Context Knowledge of the movements and space-use patterns of wildlife is crucial for implementation of effective conservation and management actions. Such information can be difficult to obtain, especially from hard-to-capture or far-ranging taxa. Global-positioning-system (GPS) receivers that have remote data-acquisition capability via satellite-communication networks offer an effective means of tracking highly mobile animals; however, often the equipment and operational costs of these devices are prohibitive. Aim To evaluate the operational performance and potential of an inexpensive, commercially available satellite-download GPS receiver that can be easily modified for use on wildlife, and to demonstrate its utility for revealing novel information on individual animal movements in an important wildlife management context. Methods We added external batteries and supplementary waterproofing to ‘off-the-shelf’ SPOT Trace® GPS receivers (~$120 USD; Spot LLC, Covington, LA) that transmit recorded location data to users through the Globalstar satellite network. We then deployed these devices on eight wild black swans (Cygnus atratus) inhabiting a large inland marine harbor adjacent to Auckland International Airport and assessed the GPS units’ operational performance and overall cost effectiveness. Key results During field trials with the tracking devices lasting up to 25 days we were able to collect thousands of precision location observations from the swans without the need for recapture. Cost-per-fix was only ~$0.04 USD – up to an order of magnitude lower than some satellite-download GPS receivers manufactured specifically for wildlife. We provide novel information about the swans’ patterns of activity, movement, space-use, habitat preferences and responses to actions taken by airport staff to scare problem individuals from threat zones. Conclusions User-modified satellite-download GPS devices can be a highly cost-effective means of tracking the movements of animals. Implications Knowledge of where and when swans present the greatest likely threat to air traffic and how they respond to displacement from restricted areas near the airport will be useful in devising threat-management plans. The ready availability of affordable remote-download GPS receivers will provide many new opportunities to study the movement and/or space-use patterns of wildlife and incorporate such information into a broad range of research and management programs.

Dingoes at the Doorstep: Home Range Sizes and Activity Patterns of Dingoes and Other Wild Dogs around Urban Areas of North-Eastern Australia

Simple summary

Conflicts with dingoes and other wild dogs are becoming increasingly common in and around urban areas of Australia. A lack of basic information about wild dog movement ecology hampers efficient planning and allocation of resources to mitigate human–wild dog conflicts. We captured, collared and released 37 wild dogs in urban areas of north-eastern Australia to investigate their movement ecology. In general, wild dogs occupied small fragments of bushland within an urban matrix, were active at all times of the day, and lived within a few hundred meters of houses and humans at all times. We conclude that wild dog management strategies in urban areas should focus on the mitigation of impacts at the individual or group level, and not population-level reductions in numbers.

Abstract

Top-predators around the world are becoming increasingly intertwined with humans, sometimes causing conflict and increasing safety risks in urban areas. In Australia, dingoes and dingo × domestic dog hybrids are common in many urban areas, and pose a variety of human health and safety risks. However, data on urban dingo ecology is scant. We GPS-collared 37 dingoes in north-eastern Australia and continuously monitored them each 30 min for 11–394 days. Most dingoes were nocturnal, with an overall mean home range size of 17.47 km². Overall mean daily distance travelled was 6.86 km/day. At all times dingoes were within 1000 m of houses and buildings. Home ranges appeared to be constrained to patches of suitable vegetation fragments within and around human habitation. These data can be used to reallocate dingo management effort towards mitigating actual conflicts between humans and dingoes in urban areas.

Fire and grass cover influence occupancy patterns of rare rodents and feral cats in a mountain refuge: implications for management

Context Feral cats (Felis catus) are implicated in the ongoing decline of Australian mammals. New research from northern Australia suggests that predation risk from feral cats could be managed by manipulating fire regimes to increase grass cover. Aims We investigate the role of fire history and hummock grass cover in the occurrence of feral cats and rare rodents, including the critically endangered central rock-rat (Zyzomys pedunculatus), in a mountain refuge in central Australia. Methods We installed 76 camera stations across four sites in the West MacDonnell National Park and used occupancy modelling to evaluate the influence of recent fire (within 5 years), hummock grass cover and ruggedness on feral cat and rodent occupancy. Key results Occupancy of the central rock-rat was positively associated with areas burnt within the past 5 years – a relationship probably driven by increased food resources in early succession vegetation. In contrast, the desert mouse (Pseudomys desertor) was detected at locations with dense hummock grass that had remained unburnt over the same period. Feral cats were widespread across the study area, although our data suggest that they forage less frequently in areas with dense hummock grass cover. Conclusions Our results suggest that fire management and grass cover manipulation can be used as a tool for rodent conservation in this environment and potentially elsewhere in arid Australia. Implications Creating food-rich patches within dense hummock grasslands may allow central rock-rats to increase occupancy while simultaneously affording them protection from predation. Landscape-scale wildfire resulting in a single post-fire vegetation age class is likely to be unfavourable for native rodents in this environment.

GPS collars are more efficient when collecting high-frequency data

Selecting an appropriate fix schedule has a pivotal role when using GPS collars. On the basis of deployments of GPS collars on 35 cats, we report on an often overlooked consideration: that GPS units are more efficient collecting data at high frequencies (15 min between fixes in this study) than low frequencies (>2 h between fixes).

Using complementary remote detection methods for retrofitted eco-passages: a case study for monitoring individual koalas in south-east Queensland

Context Vehicle-strike has been identified as a key threatening process for koala (Phascolarctos cinereus) survival and persistence in Australia. Roads and traffic act as barriers to koala movement and can impact dispersal and metapopulation dynamics. Given the high cost of wildlife mitigation structures such as purpose-built fauna-specific underpasses or overpasses (eco-passages), road construction and management agencies are constantly seeking cost-effective strategies that facilitate safe passage for fauna across roads. Here we report on an array of detection methods trialled to verify use of retrofitted road infrastructure (existing water culverts or bridge underpasses) by individual koalas in fragmented urban landscapes in south-east Queensland. Aims The study examined whether the retrofitting of existing road structures at six sites facilitated safe passage for koalas across roads. Our primary objective was to record utilisation of retrofitted infrastructure at the level of the individual. Methods We used a combination of existing monitoring methods such as GPS/VHF collars, camera traps, sand plots, and RFID tags, along with a newly developed animal-borne wireless identification (WID) tag and datalogging system, specifically designed for this project, to realise the study aims. Key results We were able to verify 130 crossings by koalas involving a retrofitted structure or a road surface over a 30-month period by using correlated data from complementary methods. We noted that crossings were generally uncommon and mostly undertaken by only a subset of our tagged individuals at each site (21% overall). Conclusions An important element of this study was that crossing events could be accurately determined at the level of the individual. This allowed for detailed assessment of eco-passage usage, rather than the more usual approach of simply recording species’ presence. Implications This study underscores the value of identifying the constraints of each individual monitoring method in relation to site conditions. It also highlights the benefits of contingency planning to limit data loss (i.e. using more than one method to collect data). We suggest an approach that uses complementary monitoring methods has significant advantages for researchers, particularly with reference to improving understanding of whether eco-passages are meeting their prescribed conservation goals.

ECOLOGY. Terrestrial animal tracking as an eye on life and planet

Moving animals connect our world, spreading pollen, seeds, nutrients, and parasites as they go about the their daily lives. Recent integration of high-resolution Global Positioning System and other sensors into miniaturized tracking tags has dramatically improved our ability to describe animal movement. This has created opportunities and challenges that parallel big data transformations in other fields and has rapidly advanced animal ecology and physiology. New analytical approaches, combined with remotely sensed or modeled environmental information, have opened up a host of new questions on the causes of movement and its consequences for individuals, populations, and ecosystems. Simultaneous tracking of multiple animals is leading to new insights on species interactions and, scaled up, may enable distributed monitoring of both animals and our changing environment.

A review of home-range studies on Australian terrestrial vertebrates: adequacy of studies, testing of hypotheses, and relevance to conservation and international studies

Describing the spatial requirements of animals is central to understanding their ecology and conservation needs. I reviewed 115 studies describing the home ranges of Australian terrestrial vertebrates that were published during 2001–12. Understanding the features that characterise best practice can guide future studies. I aimed to: evaluate the adequacy of these studies, examine the use of current analysis techniques, examine the application of home-range knowledge to species’ management, and examine hypotheses that seek to explain the size and location of home ranges. The reviewed studies were unevenly distributed across taxa with a majority (68%) involving mammals compared with birds (12%), reptiles (19%) and frogs (1%). Many studies had various shortcomings, suggesting that they had not fully described home ranges; many (41%) involved 10 or fewer individuals, ≤50 locations per individual (44%), and spanned periods of ≤3 months (46%). Studies of short duration risk underestimating home-range area and overlooking seasonal habitat use. Global positioning system telemetry was used in 10% of Australian studies. Many were also of short duration. Despite frequent criticism in the literature, the Minimum Convex Polygon was the most frequently used home-range estimator (84% of studies), followed by the Fixed Kernel (45% of studies). Applying knowledge of home ranges appears to be underappreciated, with only 39% of studies explicitly aiming to address management or conservation issues. Only three studies tested hypotheses that may explain home-range characteristics. Resource (food and shelter) distribution and, in one case, its heterogeneity, shaped home-range characteristics. I found that most studies use the term ‘home range’ in an indiscriminate way. Only 11% of studies within the international literature used qualifying terms (e.g. seasonal, annual). Tracking period is shown to influence home-range estimates. Therefore, I recommend that qualifying terms be used more frequently to avoid confusion when referring to animal home ranges.

Performance of GPS collars on free-ranging bison (Bison bison) in north-western Canada

Context Global positioning system (GPS) collars are increasingly used to study animal ecology. However, understanding their real-world performance is important so that biases in data collection can be addressed. These biases may be species specific. Few studies have examined the influence of sex or temporal variation on locational fix success rates (FSR), and none has assessed GPS-collar performance on bison (Bison bison). Aims To test for sex- and temporal-based biases on the performance of GPS collars on free-ranging bison. Methods Data from 59 deployments of 37 GPS collars on 27 female and seven male bison was used to test for temporal variation and differences between sexes on collar-deployment success rates and four fix acquisition metrics. Key results Most (72.9%) of the 55 GPS collars retrieved malfunctioned before reaching their expected deployment schedule (2 years). We observed a significant difference in the performance of GPS collars deployed on male and females, with those on females functioning almost three times longer. All four fix metrics differed between sexes, with males having significantly better metrics. For females, nightly fix metrics were better than the daytime ones, whereas for males, there was no difference. We observed a significant difference in fix metrics between seasons for females, but not males. Conclusions Although the data from GPS collars may be useful in understanding animal ecology, understanding associated biases can aid in the design of field studies using, and the interpretation of results stemming from, GPS collars. Temporal variation in our study was apparent for females, but not males, and likely related to differences in habitat use and movements. Overall, sex had a significant influence on the success of GPS-collar deployments on bison, and should be examined for other species as well. Implications Bison damage to the collars was the main reason for collar failures. Researchers should plan for catastrophic failures and malfunctions when deploying GPS collars on bison, particularly adult males. Significant differences observed between daily and seasonal FSR for females were small (≤4.9%), and do not warrant post hoc treatment before analyses.

Movement patterns of an arboreal marsupial at the edge of its range: a case study of the koala

BACKGROUND

Conservation strategies derived from research carried out in one part of the range of a widely distributed species and then uniformly applied over multiple regions risk being ineffective due to regional variations in species-habitat relationships. This is particularly true at the edge of the range where information on animal movements and resource selection is often limited. Here, we investigate home range size, movement patterns and resource selection of koalas Phascolarctos cinereus in the semi-arid and arid landscapes of southwest Queensland, Australia. We placed collars with GPS units on 21 koalas in three biogeographic regions. Home range sizes, resource selection and movement patterns were examined across the three regions.

RESULTS

Habitat selectivity was highest at the more arid, western edge of the koala's range with their occupancy restricted to riparian/drainage line habitats, while the more easterly koalas displayed more variability in habitat use. There was no significant difference between home range sizes of koalas at the western edge of the range compared to the more easterly koalas. Instead, variability in home range size was attributed to spatial variations in habitat quality or the availability of a key resource, with a strong influence of rainfall and the presence of freestanding water on the home range size of koalas. Within a 580 m spatial range, movement patterns of male and female paths showed a tortuous trend, consistent with foraging behavior. Beyond this spatial range, male paths showed a trend to more linear patterns, representing a transition of movement behavior from foraging to breeding and dispersal.

CONCLUSIONS

The difference in home range movement patterns and resource use among the different koala populations shows that behavior changes with proximity to the arid edge of the koala's range. Changes in home range size and resource use near the range edge highlight the importance of further range-edge studies for informing effective koala conservation and management actions, especially when developing species-specific adaptation responses to climate change.