Sea turtles demonstrate nocturnal behavior by mostly nesting and hatching at night. Leatherbacks typically nest from early March through mid-June. This species accounts for less than 1% of the nests in Broward County. Loggerheads are the County's most common nester, accounting for 90-95% of all nests. This species tends to nest from April through early September with peak nesting in June and July. Green turtles nest from late May through early September, tending to have alternating extreme high and low nesting seasons.
If undisturbed, the female leaves the water and crawls up the beach to a point well above the high tide line. She uses her front flippers to create a primary body pit where she gets herself level with the surrounding sand. Then, using her rear flippers, she digs an egg chamber 2-5 feet deep that looks like an upside down light bulb. After resting briefly, she then fills the hole with about 80-120 ping-pong ball sized eggs, gently covers the eggs with sand, and then spreads sand over a wide area with her front flippers to camouflage the location of the chamber. She then leaves the nest site and reenters the water.
An individual loggerhead will nest 2-3 times per season, green female sea turtles will nest 3-4 times per season, both typically at 2-3 week intervals. Leatherbacks will nest 5-7 times per season at 10-day intervals (approximately). She will not nest every year but rather every other year or third year. This will depend on a number of factors including environment, food availability, genes, and parasites, and other variables. Adult sea turtles do not nurture their hatchlings, so the female never visits the nest site again.
An individual turtle will nest within 5 miles to 35 miles of the region, on average, of where they hatched and/or nested in the past, based on tagging studies. There is also evidence that the hatchlings can detect variations in the earth's magnetic field and that may be one way they navigate back.
Approximately 50% of the time, the female exits the water without digging a nest. These are called false crawls and usually occur because the turtle was disturbed or it could not find a suitable nest site. In Florida, the crawl tracks left on the beach are always made by female sea turtles and they resemble marks left by a tractor tire.