Recordings of temperature fluctuations in the nests of birds can be used to infer incubation behavior such as the frequency and duration of off-bouts. Until recently, collecting temperature recordings from a large number of nests was limited by the size and expense of data logger equipment. In this paper, we describe software we developed to help simplify the analysis of recordings of temperature or mass fluctuations over time. The software program, called Rhythm, works in conjunction with Raven, a bioacoustical analysis program, to partially automate the measurement of incubation off-bout duration and related statistics such as percent constancy. This novel application of Raven combined with advances in data logger technology facilitates investigation in several areas of ecological and behavioral research.