Global climate change is already contributing to the extirpation of numerous species worldwide, and sensitive species will continue to face challenges associated with rising temperatures throughout this century and beyond. It is especially important to evaluate the thermal ecology of endangered ectotherm species now so that mitigation measures can be taken as early as possible. A recent study of the thermal ecology of the federally endangered blunt-nosed leopard lizard (Gambelia sila) suggested that large shade-providing shrubs act as thermal buffers which allow them to maintain surface activity without overheating. We replicated this study and added a population of G. sila with no access to large shrubs to compare the thermal ecology of G. sila populations in shrubless and shrubbed sites. We found that G. sila without access to shrubs spent more time inside rodent burrows than lizards with access to shrubs. Lizards from a shrubbed site had poorer thermoregulatory accuracy than G. sila from a shrubless site, suggesting a trade-off between surface activity and thermoregulatory accuracy. The continued management of shrubs and of burrowing rodents at G. sila sites is therefore essential to the survival of this endangered species.