Fig. 7

Figure depicting: a GPS data for a wood turtle (Glyptemys insculpta) tracked in Virginia, USA; (b) the total distance traveled estimated via conventional straight line displacement (SLD), model-smoothed SLD, and continuous-time speed and distance estimation (CTSD) approach using progressively thinned data; (c) the daily distance traveled again using conventional SLD, model-smoothed SLD, and CTSD; and (d) CTSD instantaneous speed estimates, ±95% CIs, averaged over a 24hr cycle. The gray circles in panel (a) depict the 50% error circles for GPS location estimates, the trajectory the most likely path between those locations, colored by the instantaneous speed estimates, while the gray shading in panel (d) depicts night time. Note how the measurement error is larger than the scale of the turtle’s movement (panel a) and, as a result, SLD estimates become dominated by error driven bias as the sampling frequency is increased (panel b), and vary substantially from day to day (panel c). Model-smoothing provided a reasonable, but insufficient correction to the error induced bias. In contrast, by accounting for the error structure of the telemetry data, the CTSD estimates are consistent across sampling frequencies, and suggest relatively consistent movement behavior throughout the study period. Panel (d) depicts how the turtle’s tends to move more in the early morning, with minimal movement throughout the rest of the day