Understanding and geo-referencing animal contacts: proximity sensor networks integrated with GPS-based telemetry

Background: In animal ecology, inter-individual encounters are often investigated using automated proximity loggers. However, data acquired are typically spatially implicit, i.e. the question 'Where did the contact occur?' remains unanswered. To resolve this issue, recent advancements in Wireless Sensor Network technology have facilitated the geo-referencing of animal contacts. Among these, WildScope devices integrate GPS-based telemetry within fully distributed networks, allowing contact-triggered GPS location acquisition. In this way, the ecological context in which contacts occur can be assessed. We evaluated the performance of WildScope in close-to-real settings, whilst controlling for movement of loggers and obstacles, performing field trials that simulated: (1) different scenarios of encounters between individuals (mobile-mobile contacts) and (2) patterns of individual focal resource use (mobile-fixed contacts). Each scenario involved one to three mobile and two fixed loggers and...