Microhabitat matters Understanding how our warming climate affects vulnerable species is of paramount importance. However, predicting responses is complicated because species are complex and may adapt or respond in distinct ways. Riddell et al. compared a century-old dataset on species richness in the Mojave against modern surveys to measure climate-related changes in bird and small mammal communities. They found little change in mammal richness or occupancy but large declines across birds. They attribute these differences to differences in microclimate opportunities: Specifically, mammals can mitigate temperature impacts through burrowing, whereas birds are generally more exposed. Science , this issue p. 633