From 1991-1993, we conducted an intensive mark-recapture study of an i
sland population of Florida box turtles, Terrapene carolina bauri. We
used models based on the Jolly-Seber open population model to estimate
abundance, after first examining the capture histories for violations
of the underlying assumptions of mark-recapture analysis with goodnes
s-of-fit tests contained in the program RELEASE. Some violations were
detected, resulting in low estimates. We estimated that 544 (415-672 a
pproximate 95% confidence interval) adult box turtles inhabited the so
uthern 36.4 ha of Egmont Key in the summer of 1993. This estimate is s
imilar to those of conspecific populations studied in more northern ar
eas and provides a reliable initial estimate with which to monitor pop
ulation trends in the future. Adult capture probabilities ranged betwe
en 0.09 and 0.30. Weekly survival probabilities for adults ranged betw
een 0.94 and 1.00. There were significant differences in capture histo
ries between adults and juveniles, indicating differences in survival
and/or capture probabilities. Increased movement and activity of indiv
iduals on the study area during two survey periods, one after a severe
storm and the other during the fruiting season of a favorite food sou
rce, was verified with one of the goodness-of-fit tests.