NEST-SITE SELECTION BY SEA-TURTLES

The distribution of 38 nests of loggerhead turtles (Caretta caretta) o n beaches on Sanibel and Captiva islands, south-western Florida (26 de grees 26'N 82 degrees 16'W), and of 70 first digging attempts by green turtles (Chelonia mydas) on Ascension Island (7 degrees 57'S 14 degre es 22'W), was quantified. For loggerhead turtles on Sanibel and Captiv a, nests were clumped close to the border between the open sand and th e supra-littoral vegetation that backed the beaches. This spatial patt ern of nests was closely reproduced by assuming simply that turtles cr awled a random distance above the most recent high water line prior to digging. In contrast, green turtles on Ascension Island clumped their first digging attempts on the uneven beach above the springs high wat er line, crawling up to 80 m to reach this beach zone.