Hot under the collar: the failure of radio-collars on black rhinoceros Diceros bicornis

Abstract

AbstractRadio-collaring is widely used as a monitoring tool in the conservation of the black rhinoceros Diceros bicornis. We examined rates and causes of radio-transmitter collar failure on black rhino in the Sinamatella Intensive Protection Zone (IPZ), Zimbabwe, between September 1993 and February 2000. Two collar designs, hose and strap, were fitted on immobilized rhinos in four main collaring operations. Eighty nine collars were monitored: 28 hose and 61 strap. Within 12 months of placement, all hose collars had failed. Of the strap collars, 73 per cent of those on males and 44 per cent on females had failed within 12 months. Failure rates were significantly higher in males for both collar types. For strap collars older males had higher failure rates than younger males. There was some evidence of a higher failure rate of strap collars during the wet season. Thirteen per cent of strap and 4 per cent of hose collars were removed because of poor transmission; 15 per cent of strap collars were removed because of injury. The implications of collar failure rates and the use of radio-collaring as a routine protection and /or monitoring strategy are discussed.