Each dual-equipped puffin had a moult period inferred to begin in September, while two had a second inferred moult period beginning in mid-February (table 1 & figure 3). There was some variation in the duration of moult, from 31 to 54 days. During inferred moult periods, the percentage of time spent dry according to raw immersion signals was 12.4%, while it was reduced to 4.2% when adjusted for leg tucking using data from a single leg. When data streams from both legs were corrected for tucking and combined, the proportion of time spent dry during inferred moult was 0.1%, compared to 2.4% for the rest of the non-breeding season. There was no marked increase in percentage of time spent leg tucking when undergoing moult (supporting information), consistent with observations of captive puffins (M. Huwiler, Tierpark Bern, pers. comm).