When olive ridley sea turtles are ready to lay their eggs, they make a real show of it. During part of the rainy season, from August to November, the turtles synchronize their clocks for a mass nesting event called the arribada, Spanish for “arrival.” Timed to the last quarter moon and usually lasting about five days, arribadas see anywhere from hundreds to hundreds of thousands of turtles storming Costa Rica’s Pacific beaches.
At the Nicoya Peninsula’s Ostional Wildlife Refuge, they come in droves so big that early nests are often crushed by subsequent waves of expectant turtles.
“You hear a general thudding of mother turtles patting down their nests,” says Australian photographer and conservation volunteer Annette Ruzicka, who captured this moment of relative calm as new turtles were still arriving at dawn. “At night it can be thunderous!”
The government allows community members to harvest eggs as a source of income to prevent poaching; tourists, however, should not disrupt nesting, as scared turtles have been known to flee the beach without laying a single egg. “Seeing these turtles come up to nest is almost indescribable—I was in an elated state,” Ruzicka says. “This was my last morning in Costa Rica, and I cried.”