Fig. 6

One Magellanic penguin’s dead-reckoned foraging trip at sea, lasting approximately 9 h (yellow arrow denotes the trajectory direction over time. Black track = GPS. Fifteen corrections (black circles) were made (method = “divide”). For comparison, the grey dotted track is the GPS-corrected dead-reckoned track with current integration approx. every 1 min (where possible-method = “time”) (a). Note the difference of net error between dead-reckoned positions and all available GPS fixes across the various tracks [insert = grey track] (b). Both uncorrected and corrected dead-reckoned tracks had less error after current integration (black arrows vector every 5 min) and this was reflected in the direction and magnitude of heading correction factors required per unit time (c). Heading correction factors obtained from the track corrected approx. every 1 min; the colour of the scale bar indicates the extent of the heading correction factor required)