The Great Blue Heron is one of the largest birds that occur naturally in Costa Rica. They can be found in watery environments like rivers and ponds, even artificial ones like the one in Concasa, which has been visited by a juvenile bird almost every morning from January 2018 to March of the same year. The name is misleading though, as the blue is color is rather dull on this bird. The juvenile is mostly grayish, with a darker cap, yellow eye and lower mandible, and black upper mandible. The adult shows a light dull blue on the back and wings, with brownish neck and white cheeks, maintaining the dark cap and yellow eye, but the upper mandible changes to yellow. They stalk prey from the edge of water ponds and lakes, and launch a forceful attack as fish pass by, able to snatch fish of considerable size and swallow them in one go.