Between Ambalangoda and Iduruwa the muddy Madu Ganga dances around the coastline forming a complicated network of lagoons and off-shoots. It’s fantastic birding territory and in praise of this it’s been made into a Ramsar site. Boat tours (Rs 2500 per boat, 1½ hours) are run by Maduwa River Boats from Balapitiya, a few kilometres north of Ambalangoda.