Abstract
Radar scans from an open-array Furuno marine radar at the Fundy Ocean Research Centre for Energy (FORCE) site were assessed to determine if the data could be used to monitor seabird activity at the site. The radar unit was installed to monitor the surface of the water in the Minas Passage, to determine flow rates and turbulence at the site. Radar scans from the site have been archived since 2015 in SQLite and .jpg formats, and have somewhat less resolution than the raw radar data. The archived radar scans in .jpg format were subsampled and converted into five-minute long clips, and analysed using the radR program in the R statistical programming language. After filtering out areas with persistent interference due to waves on the surface of the water, bird targets were successfully tracked using tracking algorithms in the radR program. Clips from a wide range of dates, tidal stages, and times of day were analysed to characterize seabird use at the site over four years. A general additive model was used to simultaneously account for the effects of wave clutter, date, tidal stage, time of day, and wind speed and direction on the number of bird tracks detected. The results showed a clear seasonal pattern, with few bird tracks detected in winter, peaks during spring and fall migration, and a period of high activity during the summer. Effects of time of day and tidal stage were complex, and intertwined, as the effect of tidal stage on the number of bird tracks detected was dependent on the time of day and vice versa. The effect of wind speed and direction indicated that strong southwest or southeast winds produce higher numbers of bird tracks at the site, but strong winds from other directions produce fewer bird tracks. Recommendations were made for future use of radar monitoring at the site, and for how the data from this study could be used to modify the sampling regime of observer-based seabird surveys.