The closest beach to our house is Ostional. This is a special beach with volcanic black sand that is in the Ostional Wildlife Reserve. The beach is protected because it is one of the world’s most important nesting sites for the Olve Ridley sea turtles. Because it is protected and there aren’t establishments built up along the beach, we are able to walk up and down this beach for several hours and hardly see more than a handful of people.
During the rainy season in Costa Rica, from August through December, it is even more special, because that is when the mama turtles come to Ostional Beach to lay their eggs. They come by the hundreds and even the thousands, in what is called “arribadas”, Spanish for arrivals.
Generally, the mama turtles come ashore before a new moon, but that is a general rule of thumb – they come when they come. The turtles always return to the same beach where they were born and will continue to return year after year.
A true arribada is declared when there are over a thousand turtles coming ashore to nest at the same time. During a declared arribada, the beach is “closed”, and you need a guide to walk the beach. Still, there are other days during the rainy season when there are a lot of mama turtles coming ashore to lay their eggs, and you can just walk along the beach and witness this amazing event.
(All of the lines in the sand are turtle tracks from other turtles who have completed their nesting.)
A mama turtle lays 100 or more eggs at one time. The eggs look like ping pong balls and are kind of leathery.
The chances of a baby turtle hatching and making it to the sea are slim, for multiple reasons. First, there are so many turtles laying eggs at Ostional, that the eggs in the first nests can be destroyed by the subsequent turtles laying eggs in the same place. We’ve also seen nests uncovered by new “rivulets” that spring up along the beach from bodies of water draining into the ocean because of heavy rains. And of course, there are the predators. There are always vultures and caracara birds at Ostional that will dig up nests. Wood storks come to Ostional during the rainy season for the same reason; they are not around the beach during the dry season when there are no turtle eggs. It is legal in Ostional for the locals to dig up eggs for eating. This is allowed only because there are so many eggs that aren’t going to hatch at all.
About 50 days after laying, the baby turtles emerge, often around the time of a full moon. They attempt to make their way to the sea, but their chances are slim. The vultures, caracaras, and wood storks are still around waiting for them, as are the frigate birds, who will swoop down from the sky and easily pick up a baby turtle. We’ve seen it happen right in front of us.
Again, you can just be walking along the beach and happen upon a baby turtle that has somehow made it almost to the ocean. It is frustrating to watch them go, then stop and rest and then go again. They need to make the journey on their own to develop their lungs. About the only thing you can do to help them is make sure that they are not attacked until they make it into the ocean. Even then there are predators lurking in the ocean.
Still, we are lucky to be living so near a special place where we can witness a world-famous event in nature – the nesting and hatching of the Olive Ridley sea turtles on Ostional Beach in Costa Rica.
