Fig. 3

Phylogenetic Generalised Least Squares (PGLS) model coefficients for predictors of annual shift rates (metres per year) of Breeding Bird Survey (left) and Christmas Bird Count (right) centres of abundance between 1970 and 2019. Model A assessed migratory flocking as a binary flocking vs. solo migrants for 122 species. Model B refined the assessment of migratory flocking differentiating between species that flock in age-separated and mixed-age flocks, for a reduced pool of 81 species. Red points indicate significant results inferred from credible 95th percentiles (error bars) that exclude zero