River Thames shipping coming in and out of London, in 1732 it received the world's first lightship. This became a major landmark, and was used as an assembly point for shipping. Today it is marked by Sea Reach No. 1 Buoy. The River Thames contains over 80 islands ranging from the large estuarial marshlands of the Isle of Sheppey and Canvey Island to small tree-covered islets like Rose Isle in Oxfordshire and Headpile Eyot in Berkshire. They are found all the way from the Isle of Sheppey in Kent to Fiddler's Island in Oxfordshire. Some of the largest inland islands, for example
Hilbre Islands some of which are privately owned. The most southerly building on the island is the Hilbre Bird Observatory, from which birds are continuously monitored in connection with a national network of observatories and ringing stations. In January 2011 it was announced that there would be no permanent ranger. Wirral Council said that they had had difficulty finding a ranger prepared to live without mains electricity or running water on the island. Hilbre Islands The Hilbre Islands ( ) are an archipelago consisting of three islands at the mouth of the estuary of the River Dee, the border between England and