Small airborne platforms can evolve autonomous wildlife tracking by efficiently collecting data over terrain that is difficult to access. This paper presents an unmanned aerial vehicle radio telemetry (UAV-RT) system that integrates VHF radio telemetry equipment with an unmanned aerial system. The system includes a modified hexacopter, an onboard computer, an SDR receiver, a directional antenna, and a ground control station (GCS) laptop. Preliminary experiments are conducted to demonstrate the capabilities of this system and localization accuracy of the system is quantified. Principal components analysis (PCA) and radiation pattern matching (RPM) are used for bearing estimation. Impact of flight altitude and polarization of the tag on system range are investigated. It is found that raising the antenna from the ground level to 122 m more than triples the reception distance of VHF signals.