Figure 2: Geolocator data process for a dual-equipped puffin (EJ47625) prior to moult identification, accounting for leg-tucking using raw light signals, and combining data from loggers on each leg. All data are displayed as a 2D rasterised time series. The x-axis represents calendar date, and the y-axis represents time in Universal Time Zone. A and B are the raw saltwater immersion signals from the puffin’s left and right leg respectively. C highlights the data points inferred as leg-tucking using the raw light signals. D and E show the immersion data corrected for leg-tucking events shown in C, again for the puffin’s left and right leg-mounted loggers, respectively. F shows the combined minimum of D and E, which represents the most accurate estimate of flight activity, given the data available. In F, data with a predicted solar angle of less than -6 are made semi-transparent to highlight the time series retained for moult detection. Consistent 0 values at night in F during April probably represent time spent in the burrow, i.e. neither leg wet.