Elegant Tern

A near threatened species of Tern. Medium sized with a long orange bill that slightly curves down near the end. Black crest that has a shaggy look. In breeding plumage will begin from the top of the bill and none breeding starts further back, leaving a white patch over the bill. The black continues down the back of the neck and also over the eyes. Wings and back are grey with the rest of the bird being white. You will also notice in the third and forth images the bird at the bottom. It's an immature bird, you can tell because it's bill is shorter then the adults.
Juveniles will be similar to the non-breeding birds.