Contrasting Patterns of Movement across Life Stages in an Insular Iguana Population

West Indian rock iguanas (genus Cyclura) represent the most endangered group of lizards in the world, with most taxa restricted to few or single islands. In addition to distribution and availability of resources, factors influencing optimal use of insular space in these large vertebrates may include a combination of social, ontogenetic, and long-term demographic factors. Life stage-specific dispersal and habitat use patterns have previously been characterized in Cyclura, but assessments across the lifespan are lacking. This study evaluates shifting patterns of movement in a single taxon, Cyclura nubila caymanensis. We used mark-recapture and radio tracking simultaneously to assess age- and sex-dependent variation in spatial ecology. Evidence for prolonged site fidelity among adults was consistent with territoriality-modulating space use in this long-lived taxon. Over 5-10 yr, some females were never resighted or recaptured outside of an 80-m perimeter. A notable exception was that gravid females migrated 1.17 +/- 0.91 km to utilize coastal areas during the nesting season. In contrast, neonates dispersed farther (2.32 +/- 2.26 km) and their trajectories were often nonlinear. Radio-tracked brother-sister pairs exhibited no tendency to disperse together during their first 4 wk, settling into final known locations at 4 pairwise distances of 2.16 +/- 1.74 km. Annual net displacement remained high over the first 1-3 yr of life. Our data are consistent with studies of related taxa wherein individual spatial requirements vary with population density and island size. Notably, panmixis of small island iguana populations appears largely driven by pre-reproductive movements.