Estimating overlap of daily activity patterns from camera trap data

Ridout and Linkie developed kernel-density methods to estimate and compare the daily activity patterns of animals using the timestamps recorded by camera traps, treating detection times as samples from a circular distribution. Their coefficient of overlap quantifies how much two species' temporal activity coincides, enabling study of temporal niche partitioning, predator-prey synchrony, and competition. The approach turned an often-overlooked byproduct of camera data, the time of each photo, into a rigorous behavioral tool. It became the standard method for diel-activity and temporal-overlap analyses in camera-trap studies, widely implemented in the overlap R package. The paper is heavily cited across felid and carnivore research investigating how species coexist by separating their activity in time.