The Prek Toal Bird Sanctuary is the most important breeding site for large water birds in south-east Asia. Many bird species have been driven away from neighbouring countries due to the threat from humans and loss of habitat. In 2001, the Wildlife Conservation Society set up a local conservation team to protect the colonies during the nesting seasons, and many endangered species are now thriving. Escorted by an expert local guide, cruise across Tonlé Lake to the sanctuary and spend a day spotting the various bird species. Look out for the black-headed ibis, painted storks, milky storks, spot-billed pelicans and the grey-headed fish eagle. The best time to visit is during the dry seaosn, which typically falls between December and May.