Honey bees pollinate an estimated $15 billion worth of crops each year. It is therefore vital that beekeepers assess the productivity and health of colonies in order to reassure the reproductive future of this species. Modern techniques in which beekeepers can assess honey bee colony health are labor intensive, costly, and invasive to the bees as they must open and rearrange the hive to assess colony health. A radar-based sensor, placed outside of the hive, can be used to assess colony activity and health in a non-invasive manner. In order to validate the function of this hive monitor and quantify colony health several colonies were studied with three objectives: (i) Objective I looked to affirm that bee activity was a good predictor of colony health. The relationship between honey bee colony health and hive activity of eleven hives were observed over the course of a week and then assessed for health status by estimating brood (immatures) and adult population size (total frame area occupied per colony) (ii); Objective II looked at the activity indices derived from the radar output were correlated with counts of foraging bees determined through the use of a manual counter (bees/second), an optical sensor, counting the Doppler signature tracks in recorded radar data and weather conditions; and (iii) the activity indices (RMS) vs colony health were observed for five hives over the course of two weeks. Results were characterized by statistically significant correlations in all objectives. A model was constructed in Objective I that resulted in an r2 of 0.84. This model confirmed that the radar-derived activity index was a good measure of bee activity. It also showed that solar radiation was the best weather factor predicting bee activity. Objective II affirmed that bee activity was a good predictor of colony health with an r2 of 0.53. Objective III affirmed that radar-derived activity was a good predictor of colony health with an r2 of 0.56. This data provides evidence that the radar-based hive activity monitor is a viable tool for monitoring honey bee colony health
