Widely regarded as the most important breeding ground for large waterbirds in Southeast Asia, Prek Toal Bird Sanctuary covers 120 sq miles (311 sq km) on the northwest tip of the Tonlé Sap Lake. Of the three designated biospheres on the lake, Prek Toal is the best known and is easily accessible from Siem Reap. The seasonally flooded forest abounds with numerous endangered birds such as the lesser and greater adjutants, milky and painted storks, black-headed ibis, spot-billed pelican, and grey-headed fish eagle. An ideal day trip for ornithologists and wildlife enthusiasts, Prek Toal is best visited during the dry season (Feb–Apr) – the time when migratory birds congregate in this preserve in large numbers. Visiting the sanctuary can be an expensive proposition, although the price includes transport to and on the lake, entrance to the biosphere, meals, and guided tours. Trips can be arranged usually through a guesthouse or a tour operator. Visitors can also make their own arrangements, which would include hiring a taxi to the Chong Kneas dock, from where a boat to the Prek Toal Environ mental Research Station can be hired. Those keen on witnessing the spectacular sunrises and sunsets can stay overnight at the research station, although they will have to pay for accommodations and food.
Situated in the very heart of the country, the dumb-bell shaped Tonlé Sap is Cambodia’s most prominent feature and the largest freshwater lakes in Southeast Asia. During the dry season, the lake withers to a diminutive 965 sq miles (2,500 sq km), but when the monsoon arrives it swells to a colossal 4,633 sq miles (12,000 sq km). The lake’s ecosystem supports the surrounding floodplain with more than 200 species of fish, several types of waterbirds, and reptiles such as crocodiles and turtles. Thousands of fishermen and their families live in floating villages dotted around the lake. The Tonlé Sap provides Cambodia with more than half of its annual supply of fish.