Fig. 3: Changes in the initiation of godwit migration and breeding phenology according to destination in Alaska.

a Breeding latitude of 36 geolocator-tracked individuals (orange dots; lines indicate individuals tracked in multiple years) in four years of tracking (2008, 2009, 2013, 2014; n = 12–13 per year), and assigned to Alaska region (North >64°N, n = 16; South <64°N, n = 20). The known breeding range is shown in orange. Map made with Natural Earth. b Within- and between-individual advancement of directly observed departure date from New Zealand during 2008–2020 for individuals with known breeding locations in northern (upper; n = 15 individuals observed in 3–13 years each) and southern Alaska (lower; n = 19). Date: 1 = 1 January. Figure details as described in Fig. 2b. The within-individual slope is indicated in the panel (see Supplementary Table 1b). c Timing of snowmelt (date when 33% snow-free) in the Alaska breeding range north (upper) and south (lower) of 64°N. d Start of spring green-up (date of greatest increase in Normalized Difference Vegetation Index, NDVI) in the Alaska breeding range north (upper) and south (lower) of 64°N. For c and d, black lines indicate median date across region, and shaded areas indicate 95% quantile range. Dotted lines indicate the 13-year trend (2008–2020; slope indicated in the panel), and orange lines indicate the trend during the period of geolocator-tracking (2008–2014).