NEST PLACEMENT BY LOGGERHEAD TURTLES, CARETTA-CARETTA

Nest placement by loggerhead turtles nesting on the island of Cephalonia, Greece, was examined. The spatial distribution of nests was not uniform (N = 27 nests): They tended to be laid away from the sea, but not in vegetation that backed the beach. Hatchling success (recorded for eight nests) increased significantly for nests laid further from the sea. Hence most nests were laid in positions where hatchling success was high. Six individuals were observed to nest more than once. Each of these multiple nesters showed little consistency in the distance that they nested from the sea (i.e. within-individual variation was high), and hence no significant differences in nest positioning between individuals were detected. Digging attempts in the vegetation behind the beach were frequently aborted (71% of attempts), but attempts in the open sand between the vegetation and the sea were aborted less often (11% of attempts). Sand temperatures at the depths where eggs incubated were higher further from the sea. The implications of nest placement for hatchling sex ratio are discussed. © 1993 The Association for the Study of Animal Behaviour. All rights reserved.