 The size of the island is a best estimate as different sources cite different sizes for the island; while the oldest estimates put it at around the GIS system puts it at The island is open for visitors; although, as of the summer of 2006, it was getting relatively few of them.The island is the largest one in Greenwich waters.More than half of the island (on the west side) is a bird sanctuary off-limits to members of the public without permission to visit.