Migrating animals have for a long time been tracked by recapturing tagged individuals. More recently, radio-telemetry, which requires an observer to physically follow the tagged animal, has been used.

Animal migration : a context for using new techniques and approaches / Keith A. Hobson and D. Ryan Norris -- An introduction to light stable isotopes for use in terrestrial animal migration studies / ...

Today's ecologists have more data than ever before to help monitor and understand the world's biodiversity. Yet researchers are still working to get more detailed information to better combat ...

A worldwide sensor network allows for tracking of animals on their journeys. National Geographic’s “Incredible Animal Journeys” follows these great quests. An inside look at the “Incredible Animal ...