Costa Rica: Ancient ritual

All day our group of citizen scientists waits patiently for the most exciting part of the day to come after sunset. It’s the reason we came to Costa Rica: to walk on night time beach patrols to find nesting giant leatherback and other sea turtles. We feel a great sense of purpose making sure we find the turtles in order to relocate their eggs to a guarded hatchery to save them from poachers who also patrol these same beaches. We have saved turtle nests every night except our first.

Working together with our local partner Latin American Sea Turtles, the Biosphere Expeditions team has 7 km of beach to patrol each night. The earliest night patrols may start just after dark at 19:30 and the last group leaves closer to midnight. To prepare for these 4 hour, 10 km night-walks, each person dresses in dark trousers and a dark shirt to stay invisible to the turtles. Closed-toed shoes protect feet from logs and rocks on the dark beach. Other gear includes a backpack to carry water for the trek and a red-light headlamp for conducting the data collection around the turtle. And of course a pack with data recording sheets, small metal number tags and tiny electronic tags, similar to the ones found used on domestic pets. By reading these tags it can be determined if a turtle is returning to the same area to nest multiple times in the same season or in subsequent years.

Leatherbacks are huge and you can feel the ground vibrating when they thump down their 75 cm flippers to drag their 180 cm long body over the sand. We watch for 15 minutes as the turtle seems to be investigating the dark beach for the best place to dig her nest. Two human figures venture towards us and we’re happy to see it’s the coast guard, who are patrolling the beach to catch poachers. We stop them and point out the turtle and they stand by and marvel at her size, which is briefly illuminated by flashes of lightening.

Soon sand is flying away from the turtle as she flings her flippers to remove the surface sand to get to the perfect sand to dig the nest cavity. We stand back and wait for the moment to approach. She starts gently digging down into the sand with her hind flippers and we kneel behind her with our red headlamps on. Fifteen minutes later we insert a large, clear, thick plastic bag into the hole in the sand. Cynthia and I hold the bag open beneath the gentle soft hind flippers as the turtle drops large white eggs the size of pool balls into the bag, one or two at a time. The turtle smells a bit like fish, and she is quiet and still, just flexing her short tail every few seconds to drop another egg, over 80 total. It’s so incredible to witness this ancient ritual, repeated around our beleagured planet’s beaches since the time of the dinosaurs. We watch the eggs fall, the pile of eggs building up in the bag, feeling the soft skin of her feet pressing the backs of our hands. Soon smaller yolk-less eggs start coming out, and we know it’s almost time to pull the bag out before the turtle starts to cover the nest.  Cynthia and I pull the heavy bag out together and gently drag it up onto the beach behind the turtle. We quickly twist it closed and cover it with cool sand so we can collect the data on the turtle. We stretch the measuring tape across the turtle’s back and call out the numbers to Shawn who records all the data. Fabian reads out the tag numbers on her flippers.

We say goodbye to our beautiful turtle who is covering the empty hole and we promise to take good care of her eggs. Sean and Fabian take turns carrying the 5 kg bag of eggs back to the hatchery. Its not easy work, and hands and arms ache over the 1.5 hour walk back down the dark beach. But now we have a mission, to get these eggs to their new incubating place in the safe hatchery, guarded from marauding poachers. A meteorite streaks across the sky in front of us while we stride down the beach and we joke about how these eggs must be infused with good luck from the lightning that flashed during their appearance. Maybe one of the baby turtles that hatches from our eggs, will be fast as lightning, escaping all the predators, and return to father new baby turtles when he’s fully grown 15 years from now.

Since our arrival:

8 May: 1 nest saved and taken to hatchery where Barb, Phil, Cynthia re-burried it. Poachers got 2 nests

9 May: 2 nests saved, one by Barb and Cynthia and eggs brought to hatchery where Lucy and Simona re-burried 1 clutch of eggs at hatchery, Poachers got 1 nest.

10 May: 2 nests saved, one by Fabian, Sean, Cynthia and Lucy with 88 normal and 20 yolk-less eggs. 1 nest poached.

11 May: 2 nests saved, one with 83 eggs plus 14 yolk-less eggs. No poached nests.