Genetic consequences of interglacial isolation in a steppe bird

► Temperate fauna expanded in post-glacial periods and steppe fauna in glacial ones. ► Relative time in isolation/connectivity vary among populations of both faunal groups. ► We estimated population differentiation and divergence times of Tetrax tetrax. ► Expansions in glacial periods resulted in low genetic diversity and differentiation. ► Brief isolation and long exchange periods drives evolution on steppe-adapted species.