We completed a 3-yr demographic study of the rare Florida scrub lizard, Sceloporus woodi Stejneger, in a small habitat fragment. Censuses were conducted at 2–7 d intervals, with all hatchlings marked and monitored for survival. Field and laboratory observations were used to estimate fecundity. Survival and fecundity data were combined to estimate population growth rate. Sensitivity of the population growth rate to changes in survival and fecundity was examined by both retrospective and prospective analyses.

 Survival rates of cohorts declined throughout the study. The decline in survival rates resulted principally from the low survival rates of reproductive females and resulted, in turn, in a negative population growth rate. Subsequent visits to the study site indicated that the population did not decline to extinction, but the factors that affected survival rates are not known. We present some evidence for the potential importance of predation by snakes.