 Animal radiotelemetry

Animal radiotelemetry uses radio waves to transmit information from an instrument carried by an animal to a remote radio receiver. An animal-borne radio transmitter can supply a detectable identity signal; additional sensors can report activity or physiological measurements. The transmitted signal, the animal's estimated position and the biological quantity inferred from it are distinct stages of measurement.

For example, a location fix says where an animal was estimated to be, whereas a collar activity sensor asks whether it was moving. A 2011 study combined animal radiotelemetry with collar activity measurements in owned and unowned free-roaming domestic cats.^[ref] The combination helps distinguish two animals using a similar home range but moving at different times.

A receiver's failure to detect a tag is not automatically an animal's absence. Transmission, reception, tag retention and sampling schedule all influence the observation. A useful experiment therefore checks the instrument against known positions or known activity before interpreting its output as animal behaviour. Wildlife radio telemetry applies these tools to free-living animals in the field.