Mai Po Marshes is a nature reserve in Hong Kong. It is managed by World Wide Fund for Nature. The marshes have an area of about 1800 acres and is listed as a Ramsar site under Ramsar Convention in 1995. It provides a conservation area for mammals, reptiles, insects, and over 350 kinds of birds (including Saunders's Gull and a quarter of world's Black-faced Spoonbill population). It also has inter-tidal mangroves along with 24 traditionally operated shrimp ponds (called Gei Wai locally) to provide food for the birds. It receives 40,000 visitors annually.