Combining data from dual-equipped loggers
Immersion data from both leg tags were combined for each dual-equipped puffin, again using a time series merge implemented using the xtspackage. Proportions of time spent wet were compared pairwise for each fix interval and the higher value retained in a single data stream. This meant that even if one leg recorded dry and the other recorded wet for the same time interval, the “wet fix” was preferentially retained. If one leg was submerged, then the puffin must have been resting on the water, and the “dry fix” was an instance of leg-tucking not captured by methods described in the previous section.