Fig. 1

Unprocessed Argos Kalman filter (KF) locations (gold points) and error ellipses (pale blue with black borders) for (a) hawksbill turtle (HBTU) and (b) southern elephant seal (SESE). Temporally sequential but spatially distant locations are connected by dashed blue lines. Scale bars provide an indication of the magnitude of errors. The extreme outlier location at top right (a) is approximately 650 km distant from the preceding and following locations, and has a vastly underestimated error ellipse