Fig. 2.

Changes in body mass between 1964 and 2020 for each of the 15 species. Eight species experienced a decrease in body mass, 2 an increase (lines of best fit are included for these species) and for 5 there was no detectable change (see Table 2 for lines of best fit and regression analyses output). Partial migrants are shown with blue dots and full migrants with orange. T. iliacus is shown with grey dots as it is a winter migrant so was not included in comparisons of body mass between migratory strategies