The large-scale capture of eastern grey kangaroos (Macropus giganteus) and red kangaroos (Osphranter rufus) and its application to a population management project.

Abstract

OBJECTIVE: A large-scale capture method was developed to enable sterilisation of a macropod population in western Sydney from 2005 to 2018. METHODS: Until March 2007, free ranging eastern grey kangaroos and red kangaroos were herded into purpose-built 15 m diameter capture yards (CYs) for darting with a projectile syringe. From March 2007 onwards, animals were free-range darted in large areas without herding. Kangaroos were darted with 1.33-5.10 mg/kg tiletamine/zolazepam and 0.01-0.02 mg/kg medetomidine, ± 0.03 mg/kg acepromazine. Deaths were monitored. Population counts were performed annually. RESULTS: There were 5825 capture events involving 3963 kangaroos. Over 85% of all captures occurred from 2005 to 2008. Of all reported deaths (n = 523), 135 were attributed to ill health. Musculoskeletal injuries incurred during capture were the main project-related cause of death (n = 116). Post capture myopathy was uncommonly diagnosed following capture (n = 19). CONCLUSION: The herding and capture method enabled a large number of kangaroos to be mobilised and captured with low mortality rates, and the use of CYs resulted in fewer capture-related injuries and deaths than free-range capture. The drug doses and combinations used for darting were safe and effective, and the capture technique was successfully applied to a population management project.