178 birds species from 39 families belong to 17 order defined in the research, carried out between 2001-2003 in Lake Acarlar in northeastern Marmara region. Passeriformes has been determined to be the most dominant order while Pelecaniformes, Cuculiformes, Caprimulgiformes have been to be the least dominant order in the research area. In two years 73632 individuals have been defined at Lake Acarlar, having a diversity index of 36,41. The Lake which is a rich ornithological area, faces various problems due to increasing population. Some of these problems are unauthorized hunting, damage to the forest ecosystem, attemps to create agricultural fields and Silk Road Free Zone Project.