Radio transmitters for migratory birds and many other species of animals have progressed from short-range, very high frequency (VHF) packages in the 1960s, to platform transmitter terminals (PTTs) in the 1990s, and global positioning system (GPS) transmitters in the 2000s. Miniaturization of transmitters has resulted in availability for use on a great number of species.
WERC scientists are internationally known for their expertise in the use of satellite and radio telemetry applications in wildlife studies. Examples of radio telemetry projects include determining the local and regional movements of waterbirds in San Francisco Bay, studying the movements of desert tortoises and their uses of different habitat types, evaluating the distribution and habitat use of giant garter snakes, and monitoring California sea otter survival. Satellite telemetry is used on a wide range of migratory birds species to determine long distance migration routes, nesting areas and any role they may play in serving as vectors for diseases such as avian influenza. GPS transmitters have been used to evaluate the movement of bobcats across networks of reserves in Southern California and on bighorn sheep in the Joshua Tree National Park to examine seasonal home range and distribution and whether recreational activity is affecting patterns of space/habitat use.