Figure 3: Inferred timing of flightless moult in four dual-equipped puffins. Immersion data were combined between two geolocators for each puffin. The green line represents time spent dry per day (propfligth) and the blue line is the 5-day rolling average of this (propflight-5). The blue bar underneath each plot represents moult inferred on the first pass of the moult identifiation process, the red bar represents a potential second flightless moult identified by the second pass.
All moult periods occurred close to equinox periods, when the latitudinal accuracy of light level geolocation is greatly reduced. The average position of inferred moult was used to graphically represent moult location (figure 4), given that puffins are unlikely to move extensively when flightless, and most of the variation in location during moult is almost certainly due to error in location estimates. Both individuals with two inferred moult periods had more extensive migrations than those with one (table 2), with the autumn flightless moult occurring when they were furthest from their colony and the spring moult when much closer to the colony (figure 4).