Strict allopatric speciation of sky island Pyrrhula erythaca species complex

•The statistical model selection procedure favors strictly allopatric speciation.•Ecological niche modeling suggests climatic niche conservatism.•Divergence without gene flow might have been driven by niche conservatism.•Ecology can have a dynamic role in diversification of sky island species complex.•Genetic and behavioral data suggest two full species in traditionally defined Pyrrhula erythaca.