This past October, I was lucky enough to travel to Nosara and see one of the most amazing spectacles I have ever witnessed: the Ostional arribada! Each year between July and December, thousands upon thousands of Olive Ridley sea turtles make their way to the beaches of Ostional National Park in order to lay their eggs. The eggs take several months to incubate, which means that during the time I was there we were able to witness both adults laying eggs as well as babies hatching!
The arribada occurs around a week before the new moon and typically lasts just under a week. During this time, upwards of hundreds of thousands of turtles will make land to lay eggs.
An extremely low percentage of eggs will actually make it to adulthood. Only an estimated one in one thousand hatched eggs will reach adulthood. Because so many of the eggs end up crushed or dug up by the thousands of turtles competing for space to lay their own eggs, this is one of the only places in Costa Rica where it is legal to harvest the eggs. Locals will collect eggs only in the first day or two of the early arribadas, as these eggs have almost no chance at eventually hatching.
Seeing thousands of turtles making their way on shore to lay eggs, followed by hundreds of tiny turtles hatching and dashing to the ocean, was by far one of the most incredible nature events I have ever witnessed.