Fifteen years of satellite tracking development and application to wildlife research and conservation

small satellite-based tracking system that is light enough to be carried on birds was developed in the 1980s at the Applied Physics Laboratory. A new, more capable generation is now under development that will contain, in addition to the Argos tracking platform transmitter terminal, a global positioning system receiver and a complement of advanced sensors. The sensors may include a digital audio capture system and a black-and-white charge-coupled device camera. The history of the program and plans for future development are discussed.