Aerial tracking of radio-marked white-tailed tropicbirds over the Caribbean Sea

We radio-marked nesting white-tailed tropicbirds at Culebra National Wildlife Refuge, Puerto Rico, and tracked them from a Cessna 182 during flights over the open sea. Locations of the birds were determined using standard aerial telemetry techniques for side-facing Yagi antennas. We used strut-mounted, 4-element Yagi antennas connected to a switchbox and scanning receiver. By recording bearing and distance from at least 1 of 3 aeronautical navigation beacons, the position of the aircraft and the bird could be estimated with an error of about 2 km. On several occasions we plotted the general heading of a bird and then relocated and tracked the same bird on the following day. Our method of aerial tracking and navigation was useful for tracking birds over the sea to at least 116 km from the breeding colony