Drones are often considered an unobtrusive method of monitoring terrestrial wildlife; however research into whether drones disturb wildlife is in its early stages. This research investigated the potential impacts of drone monitoring on a large terrestrial mammal, the eastern grey kangaroo (Macropus giganteus), in urban and peri-urban environments. We assessed the response of kangaroos to drone monitoring by analysing kangaroo behaviour prior to and during drone deployments using a linear modelling approach. We also explored factors that influenced kangaroo responses including drone altitude, site characteristics and kangaroo population dynamics and demographics. We showed that drones elicit a vigilance response, but that kangaroos rarely fled from the drone. However, kangaroos were most likely to flee from a drone flown at an altitude of 30 m. This study suggests that drone altitude is a key consideration for minimising disturbance of large terrestrial mammals and that drone flights at an altitude of 60–100 m above ground level will minimise behavioural impacts. It also highlights the need for more research to assess the level of intrusion and other impacts that drone surveys have on the behaviour of wildlife and the accuracy of the data produced.

Advances in drone technology have given rise to much interest in the use of drone-mounted thermal imagery in wildlife monitoring. This research tested the feasibility of monitoring large mammals in an urban environment and investigated the influence of drone flight parameters and environmental conditions on their successful detection using thermal infrared (TIR) and true-colour (RGB) imagery. We conducted 18 drone flights at different altitudes on the Sunshine Coast, Queensland, Australia. Eastern grey kangaroos (Macropus giganteus) were detected from TIR (n=39) and RGB orthomosaics (n=33) using manual image interpretation. Factors that predicted the detection of kangaroos from drone images were identified using unbiased recursive partitioning. Drone-mounted imagery achieved an overall 73.2% detection success rate using TIR imagery and 67.2% using RGB imagery when compared to on-ground counts of kangaroos. We showed that the successful detection of kangaroos using TIR images was influenced by vegetation type, whereas detection using RGB images was influenced by vegetation type, time of day that the drone was deployed, and weather conditions. Kangaroo detection was highest in grasslands, and kangaroos were not successfully detected in shrublands. Drone-mounted TIR and RGB imagery are effective at detecting large mammals in urban and peri-urban environments.

Context: As urban landscapes proliferate globally, the need for research into urban wildlife interactions is magnified. The eastern grey kangaroo (Macropus giganteus) is a widespread species commonly involved in wildlife–vehicle collisions in urban areas in Australia. Despite the many urban kangaroo populations and associated conflicts with human activities, few studies have examined how eastern grey kangaroos interact with, and are affected by, the urban matrix. Aims: The present study aimed to quantify kangaroo demography, movements, habitat utilisation and exposure to risks during a period of intensive urban development in a rapidly changing suburb located in a region undergoing high urban growth rates. Methods: We utilised foot-based census surveys, global positioning system (GPS) collars, direct observations and reports of wildlife mortality between 2014 and 2016. Geographical information systems (GIS) were used to integrate GPS-tracking data with spatial layers, to quantify kangaroo movements and habitat utilisation. Key results: The kangaroo population underwent a steep decline and kangaroo–vehicle collisions were the main source of mortality (73%) during the study period. Kangaroos were regularly exposed to the risk of injury, with roads intersecting many parts of their home range. Kangaroos showed positive habitat selection both for lawn and forest habitats and kangaroo movement and presence at the study site were influenced by high-quality forage and cover. Conclusions: The present research has highlighted that despite areas of suitable habitat remaining, road-kill was a major contributor to localised kangaroo-population decline. We showed that habitat preferences of eastern grey kangaroos in this urban area were consistent with those in natural landscapes. Implications: The present study is the first to implicate kangaroo–vehicle collisions as the major factor in population decline in kangaroos. These findings can be utilised to guide design and placement of kangaroo–vehicle collision mitigation and assist in planning of urban areas, particularly where kangaroo populations are in decline. Local extirpation of urban kangaroo populations would be greatly reduced by incorporating site-specific kangaroo habitat preferences and existing patterns of kangaroo habitat use in infrastructure planning. The study has contributed to our understanding of the effects of roads on urban wildlife in general and highlighted the importance of landscape permeability.

Urbanization significantly impacts the health and viability of wildlife populations yet it is not well understood how urban landscapes differ from non‐urban landscapes with regard to their effects on wildlife. This study investigated the physiological response of eastern grey kangaroos (Macropus giganteus) to land use at a landscape scale. Using fecal glucocorticoid metabolites (FGM) we compared stress levels of kangaroo populations in urban and non‐urban environments. We modeled FGM concentrations from 24 kangaroo populations against land use (urban or non‐urban) and other anthropogenic and environmental factors, using a linear modeling approach. We found that land use was a significant predictor of FGM concentrations in eastern grey kangaroos with significant differences in concentrations between urban and non‐urban populations. However, the direction of the relationship differed between northern and southern regions of Australia. In the northern study sites, kangaroos in urban areas had significantly higher FGM levels than their non‐urban counterparts. In contrast, in southern sites, where kangaroos occur in high densities in many urban areas, urban kangaroos had lower FGM concentrations than non‐urban kangaroos. Rainfall and temperature were also significant predictors of FGM and the direction of the relationship was consistent across both regions. These results are consistent with the contrasting abundance and persistence of kangaroo populations within the urban matrix between the two study regions. In the northern region many populations have declined over the last two decades and are fragmented, also occurring at lower densities than in southern sites. Our study indicates that it is the characteristics of urban environments, rather than the urban environment per se, which determines the extent of impacts of urbanization on kangaroos. This research provides insights into how the design of urban landscapes can influence large mammal populations.

Human population growth and the resultant expansion of urban landscapes are drivers of biodiversity loss globally. Impacts of urbanisation on wildlife are not well understood, although the importance of preserving biodiversity in urban areas is widely recognised. The eastern grey kangaroo (Macropus giganteus), a common species of large macropod, can be found in high densities in many urban landscapes across Australia. South East Queensland is a subtropical region of Australia that has experienced high rates of urban expansion. Human population growth in the region has resulted in widespread changes to the landscape and much of the eastern grey kangaroo’s natural habitat has been modified. Declines in kangaroo populations have been anecdotally reported; however, the impact of urbanisation on kangaroo populations has not been quantified. This study used a modelling approach, collecting data from the community, and private and government organisations to: (1) map the current distribution of eastern grey kangaroos; (2) quantify trends in kangaroo abundance; and (3) identify anthropogenic drivers of changes in kangaroo abundance in the region. Of the kangaroo populations identified, 42% were reported to have undergone an overall decline in abundance since 2000. Higher human population growth rate and smaller area remaining under natural land use were predictors of kangaroo population declines. Further kangaroo declines can be anticipated in the region, particularly in areas with projected human population growth rates over 80% for the next decade. This study emphasises the importance of integrated urban development over large spatial extents to mitigate impacts of urbanisation on terrestrial mammals.

Rapid increases in urban land use extent across the globe are creating challenges for many wildlife species. Urban landscapes present a novel environment for many species, yet our understanding of wildlife behavioural adaptations to urban environments is still poor. This study compared the vigilance behaviour of a large mammal in response to urbanisation at a landscape level. Here, we investigate urban (n = 12) and non-urban (n = 12) populations of kangaroos in two regions of Australia, and the relationship between kangaroo vigilance and urbanisation. We used a linear modelling approach to determine whether anti-predator vigilance and the number of vigilant acts performed were influenced by land use type (i.e., urban or non-urban), human population densities, kangaroo demographics, and environmental factors. Kangaroo behaviour differed between the two study regions; kangaroo vigilance was higher in urban than non-urban sites in the southern region, which also had the highest human population densities, however no effect of land use was found in the northern region. Season and sex influenced the vigilance levels across both regions, with higher levels seen in winter and female kangaroos. This study is the first to compare urban and non-urban vigilance of large mammals at a landscape level and provide novel insights into behavioural adaptations of large mammals to urban environments.