Biologging is the practice of attaching a device to an animal, typically to track and record the animal’s movements to better understand its conservation needs. Such tracking devices are particularly important to develop conservation strategies for animals that travel vast distances and whose movements remain largely a mystery, like migratory birds and marine species.
There are several kinds of tracking technology commonly used by researchers today. Light-level geolocators, for instance, are used to study bird migration paths by recording information about ambient light levels that can be used to determine the bird’s latitude over time. Geolocators have the benefit of being small and long-lasting due to their low energy consumption, but researchers must manually retrieve them to obtain the recorded data.
Satellite transmitters, meanwhile, periodically send a signal to an orbiting satellite that logs the animal’s GPS coordinates in real time. These can be used to track animals like sea turtles that are harder to retrieve, as highlighted in the Wild Hope episode Turtle Trackers. Unfortunately, they are still too bulky to put on smaller species.
An increasingly popular third kind of tracking device, called automated radio transmitters, sends signals to a series of radio towers. These devices are only useful in areas of the world where towers tuned to their particular frequency have been installed, but they can be much smaller and lighter than satellite transmitters, enabling them to be affixed to animals as delicate as a monarch butterfly.