We experimentally controlled brown treesnakes (Boiga irregularis) in a 5 ha study site on Guam and monitored extant lizards for a response to snake suppression. We then used functional response in extant lizards to snake suppression as a trigger to initiate reintroductions of three extirpated lizard species, with different activity patterns or microhabitat uses. These represent data from monitoring lizards in three ways: (1) nocturnal visual surveys for brown treesnakes in which all extant lizard species sighted were counted and recorded; (2) conducting mark-recapture surveys for three species of extirpated lizards that were reintroduced to the sites and; (3) the fate of two of the species that were reintroduced for individuals that we released with radio transmitters to track their fate.