In English, this bird is called Crested serpent-eagle because it can erect the feathers on its head into a "crest" and it subsists mainly by hunting reptiles - serpents and lizards. The nest is built high up in a tree, preferably near fresh water. The pair usually lays only one egg per litter. Some individuals are dark brown, but others, like this one in the photograph, are watered bluish gray with uneven spots. However, all Crested serpent-eagles always have yellow eyes and a yellowish field between the eye and the beak.