“…This has led to species differentiation (Leonard et al, 2015). Glaciation has played an important role in influencing the population size, species and community genetic structure of today’s species (Svendsen et al, 2004; Hewitt 2000, 2004), the glacial-interglacial gyrations of the same period also affected the distribution of species (Kozma et al, 2018; Zhao et al, 2013; Hung et al, 2014; Mays Jr et al, 2018), Glacial-interglacial cycles led to periodic shifts in glacial refuges for Pleistocene birds (Nadachowska-Brzyska et al, 2015), the isolation of glacier refugia will lead to the divergence of the whole genome of species, thus forming different species (Provost et al, 2022), this should be the reason why the common ancestor of S. aluco MN122823 and S. aluco OP850567 (this study) diverged at 1.59~2.51Ma, genetic divergence of the same lineage due to the isolation of refugees leads to lineage divergence. All kinds of species generally begin to migrate to the best habitat during the warm climate period (Claramunt and Cracraft, 2015), in particular, species adapted to low altitudes in the early stage of climate change will move to high altitudes at this time, resulting in the reproductive isolation of species in the two places (Wiens, 2004).…”