Post-glacial northward expansion and genetic differentiation between migratory and sedentary populations of the broad-tailed hummingbird (Selasphorus platycercus)

Unlike other migratory hummingbirds in North America, the broad-tailed hummingbird (Selasphorus platycercus) exhibits both long-distance migratory behaviour in the USA and sedentary behaviour in Mexico and Guatemala. We examined the evolution of migration linked to its northward expansion using a multi-perspective approach. We analysed variation in morphology, mitochondrial and nuclear DNA, estimated migration rates between migratory and sedentary populations, compared divergence times with the occurrence of Quaternary climate events, and constructed species distribution models to predict where migratory and sedentary populations resided during the Last Glacial Maximum (LGM) and Last Interglacial (LIG) events. Our results are consistent with a recent northward population expansion driven by migration from southern sedentary populations. Phylogeographical analyses and population genetics methods revealed that migratory populations in the USA and sedentary populations in Mexico of the pla...