Hawksbills travel throughout the tropical and subtropical waters of the Atlantic, Indian and Pacific Oceans. They are one of six species of marine turtle species found in and around the Caribbean. Other species include the Leatherback, Green, Loggerhead, Kemp’s ridley, and Olive ridley. Named for its distinctive beak-like bill and renowned for its beautiful mottled shell, the hawksbill is a relatively small sea turtle. At Jumby Bay, adult females weigh between 40 and 60 kg (88 to 130 lbs) with shells that range in length from about 75 to 95 cm (30 to 37 in).
Hawksbills feed primarily on sponges, which contain glass needles called “spicules.” It’s a wonder that hawksbills can subsist on a diet of glass! Their unique feeding habits help to maintain the delicate balance between corals and sponges in reef communities.
Female hawksbills in the Caribbean are believed to reach sexual maturity at 15 to 30 years of age. They mate while swimming and are able to store sperm for an extended period. Hawksbills prefer to nest on small, isolated “pocket beaches” with vegetation. Because they are small and agile, hawksbills are able to access maritime forest and conceal their nests within dense beach shrubbery, a unique behavior among marine turtles. Amazingly, they will travel hundreds of miles from their foraging grounds and return to the same area from which they hatched decades earlier to deposit their eggs. Nesting hawksbills show very strong nest site fidelity at Jumby Bay, returning to the same beach – and often the same section of the beach – to nest season after season.
Hawksbills generally lay four to six nests per season at two-week intervals. For example, if a turtle is observed nesting on June 1, we’d expect to see her again on or around June 15, June 29, and so forth. They do not reproduce every year, instead skipping a year or more to build up the resources necessary to produce eggs and make the long journey from foraging grounds to breeding sites. Remigration intervals – the time that elapses between successive nesting seasons – average about three years at Jumby Bay. While most females return every two, three or four years, we have recorded seven or more years elapsing between an individual female’s consecutive nesting seasons.
When the time is right, gravid females (those carrying eggs) crawl onto the beach and excavate a 50 cm (~1.5 ft) deep chamber shaped like an upside-down light bulb, using their rear flippers as scoops. Digging the egg chamber takes from about 20 minutes to more than an hour. Once the turtle has completed the digging process, she lays about 150 ping-pong ball-shaped eggs in about 15 minutes! After egg-laying is complete, she uses her rear flippers to scoop sand over the eggs and gently tamp the surface. The front and rear flippers are used to camouflage a big swath around the egg chamber so that a hungry predator would have a difficult time pinpointing the location of the nest. The entire nesting process takes close to 90 minutes to complete; however, we’ve seen some turtles successfully nest in about an hour and others remain on the beach for more than 6 hours. This ancient nesting ritual is a truly magical experience for those fortunate enough to witness it.
Hawksbill nests incubate between 55 and 70 days. After hatching out of their eggs down in the sandy nest, the tiny turtles take a day or two to rest, straighten their shells, and wait for their siblings to hatch. A drop in temperature, brought about by nightfall or sometimes rain, serves as a cue for the hatchlings to start digging. The digging power of many hatchlings allows them to successfully emerge from the sand as a group. Upon emergence, hatchlings crawl towards the brightest horizon which, in the absence of artificial lights, is where the ocean meets the sky. Once they reach the waves and get swept up into the sea, their real perilous journey is just beginning. Only about one in 1,000 hatchlings survives into adulthood.
Each female lays about 150 eggs per nest, 5 times per season, 2weeks apart, every 3years