Fig. 4

A Estimated shifts in non-breeding centres of abundance 1970–2019 for 81 analysed species in Model B. Arrows are coloured by migratory flocking behaviour – age-separated flocks (light-blue), mixed-age flocks (dark-blue) and solo (red) and transparency is set according to reciprocal error in estimated shift, such that more transparent arrows indicate lower confidence in estimates. B Phylogenetic tree of the 81 species analysed for shifts in Christmas Bird Count annual centre of abundance and incorporated into the Phylogenetic Generalised Least Squares (PGLS) model. Nodes are coloured by migratory flocking behaviour – age-separated flocks (light-blue), mixed-age flocks (dark-blue) and solo (red). C Estimated marginal mean annual shifts in Christmas Bird Count centre of abundance 1970–2019 for migratory flocking behaviour based upon 81 species of North American migratory birds in a Phylogenetic Generalised Least Squares (PGLS) model incorporating uncertainty in shift rates and controlling for biological and demographic traits. Error bars indicate standard error