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

Mark Cowan,Mark Blythman,Lesley Gibson,John Angus

doi:10.3390/ani10101914

Abstract

Simple SummaryAs 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.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.

Highlights

The relocation of native fauna out of the path of development projects, sometimes termed mitigation translocation, has dramatically increased in recent years, most likely in response to the rapid pace of urban development [1]
Excluding the animals that died within the first day after relocation and the three Global Positioning System (GPS) animals that were alive at the end of the project, the average duration of survival was 9.5 days (n = 46, SD = 14.6)
We examined camera detection data to assess whether there was a level of concordance in broad patterns of activity for GPS collared kangaroos and resident kangaroos

Summary

Introduction

The relocation of native fauna out of the path of development projects, sometimes termed mitigation translocation, has dramatically increased in recent years, most likely in response to the rapid pace of urban development [1]. As a wildlife management tool, relocation for mitigation purposes. A further complication common to relocations for mitigation purposes is that animals are often moved to an area where conspecifics occur without an understanding of the impacts on either the relocated or resident population [4]. Where development projects involve the clearing of wildlife habitat, conditions may be placed on planning approval to ensure that fauna are appropriately managed so that their welfare is not compromised. Public concerns regarding lethal methods, such as culling, often influence the choice of management option [4]

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