Lesser Crested Tern - Sterna bengalensis are a mobile species  - the colony does move from island to island in the Bu Sa'adash group on Hawar. The physiacal appearance and topography of each islands used is totally different - the island shown below the most commonly used and the more northerly of the islands, has a 2 m dune along the north shore - the balance is flat and typical of many low lying islands - sand and shell accumalation over bedrock