‘Cigueñón’ Woodstork (Mycteria Americana)

Woodstorks are frequently found at a variety of freshwater and saltwater habitats, looking for areas with receding water levels with a concentration of fish in shallow pools. It often feeds in groups submerging themselves into the water with partly opened bills sweeping to and fro, driving and concentrating fishes and then shutting their bills on contact.

Source: A Guide to the Birds of Costa Rica by F. Gary Stiles and Alexander F. Skutch