The lesser crested tern (Thalasseus bengalensis).
The genus name is from Ancient Greek Thalasseus, “fisherman” from thalassa, “sea”. The specific bengalensis means “of Bengal”, the type locality, historically referring to much of northern India and Bangladesh.
This bird breeds in subtropical coastal parts of the world mainly from the Red Sea across the Indian Ocean to the western Pacific, and Australia. Significant populations are found on the Mediterranean’s south coast. The Australian birds appear to not migrate unlike the Mediterranean birds which migrate to South Africa.
As with all Thalasseus terns, the lesser crested tern hunts for fish plunge-diving usually into salty water.
Summer sees adults with a black cap, black legs and a long sharp orange bill. The rump, central tail feathers and upperwings are grey with white underparts. The primary flight feathers darken during the summer. In winter, the forehead becomes white. The grey rump distinguishes it from related species.
There are two other orange-billed terns within the range of this species. Both are much larger and stouter-billed with the royal having a white rump and tail and the crested (which also has a grey rump) is darker overall above and has a yellower bill.