While current attention is focused on preserving the largest wetlands, millions of smaller areas have been lost to urban development. A conservative estimate is that 50 percent of wetlands have been lost worldwide. Aware that even the smallest wetlands can be used as feeding and resting habitat by numerous varieties of migratory birds, the Ramsar Convention on Wetlands was formed in Ramsar, Iran, in 1971. An international treaty sets the framework for the conservation and intelligent use of wetlands and their resources. The organization has designated 1,148 wetlands sites—totaling 96.3 million hectares—of international importance. The three smallest designated sites are all about 1 hectare (2.47 acres) in size: Hosnie's Spring, Christmas Island, Australia; fie Alcatraz, Kamsar/Boke, Guinea; and Somerset Long Bay Pod, Bermuda, United Kingdom.
