An updated checklist of the marine birds (Aves) of Golfo Dulce, southern Costa Rica

Golfo Dulce is a fjord-like embayment on the southern Pacific coast of Costa Rica, which encompasses the marine protected area of Piedras Blancas National Park. The gulf is surrounded by mangroves, rocky shores, and sandy beaches that are home to migratory and resident bird species. Here, we provide a checklist of 73 marine birds, including records of six years of annual counts and incidental observations in Golfo Dulce. This paper represents an updated bird list, based on the 1998 Basic Information Units from Instituto Nacional de Biodiversidad. We added 16 species to the list, showing the importance of maintaining a monitoring program of marine birds in the Golfo Dulce area. We have also demonstrated the valuable contributions of citizen science for obtaining scientific information.