Fig. 2

Schematic illustrating the recording and basic interpretation of proximity-logging data. a Proximity loggers are transceiver tags that both transmit and receive radio signals (see main text). In this hypothetical example, tags A and B transmit radio pulses every 20 s and are within reception range of each other between t ₁ = 65 s and t ₂ = 150 s, indicated by green dashed lines. b Simplified log file showing how the encounter is recorded in the tags’ memories (for a sample of a genuine log file, see Table 1). c At the analysis stage, the encounter between A and B can be reconstructed from their respective log files. The upper plot shows the encounter according to what tag A received, and the lower plot according to what tag B received. The disparity in start and end times for the encounter, as recorded by A and B, arises from the difference in times at which tags A and B transmit radio pulses