The last primary lowland rainforest in Sri Lanka and a UNESCO Natural World Heritage Site, Sinharaja holds 21 of the island’s 26 endemic bird species and a density of endemic life that is almost without parallel in South Asia. The mixed-species feeding flocks that move through the canopy throughout the day create a birdwatching experience that specialists consistently rate among the finest available anywhere. A guided walk here is not a nature walk with interesting birds. It is an immersion in a biological system of extraordinary complexity.