Calidris ferrugineaCalidris ferruginea, adult summer plumage starting moult to winter plumage. San Elijo Lagoon, San Diego Co., California, USA; 4 July 1981.Source: Flickr (colour corrected and dust specks removed from original)
Spotted Sandpipers (Actitis macularius) are the most numerous Sandpipers in Costa Rica, especially inland. They are neotropical migrants. This is a call from a foraging bird.