Satellite Telemetry of Large Mammals in Mongolia: What Expectations Should We Have for Collar Function?

The rapid pace of the development of satellite wildlife tracking tools has left little time for thorough testing of new equipment and identifying possible sources of technical failures. In the Gobi and Eastern Steppe region of Mongolia we deployed 98 satellite collars, collecting animal locations using the Doppler based Argos (n = 29) or the global positioning system (GPS; n = 69), on 45 Asiatic wild asses (Equus hemionus), 34 Mongolian gazelles (Procapra gutturosa), 15 Przewalski's horses (E. ferus przewalskii), eight wild Bactrian camels (Camelus ferus), and two wolves (Canis lupus). Although, we collected valuable data from little-known species in a remote environment, of 98 collars deployed, only 29 worked as good as or better than expected whereas 69 were subject to technical problems. The majority of problems had to do with a reduced performance of the Argos component (n = 12), with both the Argos and the GPS components (n = 1), or with the Argos component in combination with another unknown problem (n = 12). Further problems were caused by human error during manufacturing or deployment (n = 10), software bugs (n = 7), mechanical failures (n = 5), poor GPS performance (n = 1) and premature failures for unknown reasons (3 ≤ n ≤ 21). The better performance of Argos only collars on Mongolian gazelles and of collars not attached to an animal suggest that a large body mass reduces the Argos signal below a critical threshold. Consequently, we presently would not recommend the use of collars depending on an Argos unit for data collection or transfer on large bodied ungulates in central Asia. Although, several premature failures may have been caused by animals being poached, our failure rate remains high and indicates that managers and researchers need to be aware that there is a high risk of equipment failure when applying newly emerging satellite tracking technology. This implies logistic and financial uncertainties which may be difficult to explain to the scientific community, the public, management- and funding agencies alike. We recommend the development of a web-based platform where users and producers of telemetry products can quickly post and exchange their experiences.