Figure 1From: Islands in the sky: the impact of Pleistocene climate cycles on biodiversityThe Mexican jay is a sedentary species found in pine-oak woodlands in the sky islands in the southwestern USA and northern Mexico. Different populations have differentiated genetically within the last 10,000 years. Photo by TJ Ulrich with permission from Visual Resources for Ornithology, the Academy of Natural Sciences, Philadelphia, PA.Back to article page