The Mai Po marshes are part of the Pearl River estuary,
whose muddy shores abound with crabs, worms and mud-skippers.

Exposed at low tide, this smorgasbord of mud-life attracts both waders and the gei wai birds.

Here on the mudflats of Inner Deep Bay,
each kind of bird has its own specific feeding zone defined by the depth of the water, the length of its beak and its feeding technique.