There are various interesting varieties; Rendatleri, a roseate form, is very free.
This last is the beautiful roseate tern, Sterna dougalli; the other is the black tern, Hydrochelidon nigra, belonging to a genus in which the toes are only halfwebbed, of small size and dark leaden-grey plumage.
Ross's or the roseate gull, Rhodostethia rosea, forms a well-marked genus, distinguished not so much by the pink tint of its plumage (for that is found in other species) but by its small dove-like bill and wedge-shaped tail.
Among these are the large white crane and small crane, the blue heron, the snowy-white egret, the roseate spoonbill (Platalea ajaja), stork, bittern and many species of ducks.
