Siem Reap Bird Watching, Bird Sanctuary
There are 2 potential places where you can visit Cambodia rare endangered bird sites; 1. Boeung Pearaing & 2. Chreav Village of Tomnup 78. Both provide excellent friendly half day of bird watching tours, learn from your experienced local tour guides about many species of water/forest birds including: Comb Duck, Purple Swamphen, Comoran, Darter, Purple and Grey Heron, Adjutant, Lesser Whistling Duck, Black Headed Ibis etc.
https://www.triplekangkor.com/about-cambodia/siem-reap-things-do-see/bird-watching-bird-sanctuary/