Why use the GPS for studying animals rather than satellite
transmitters, radio transmitters (VHF tags) and geolocators?
The table below shows pros and cons of GPS technology:
GPS is for detailed spatial and temporal reconstruction of short-range movements; tags must be recovered in order to retrieve the data. Eventually, data can be downloaded remotely if GPS is connected to a GSM or blue-tooth transmitter.
Satellite transmitters based on Argos are for long-range movements and have lower spatial resolution (except the new satellite-GPS tags). Data are sent remotely to the user using satellite channels.
VHF transmitters are for short-range localization of animals. You don't get the track. Positions are estimated by triangulation and are not precise and must be recorded by the field workers. To follow the movement of an animal using VHF requires constant manpower.
GLS (geolocators): very small tags for recording movements over long distances since errors can be larger than 100 kilometers. Locations (longitude and latitude) are estimated on the basis of the duration of daylight. GLS must be recovered to retrieve the data.