5. Discussion
We conducted surveys of the two most important green peafowl populations remaining in Vietnam, and which are found in two key protected areas. The density of green peafowl was lower in Yok Don National Park than in Cat Tien National Park. Moreover, the number of calling birds in Yok Don National Park recorded in 2013 was significantly lower than that observed in 1998. The higher density estimate from Cat Tien may be a result of the different distributions of habitat patches in the two parks, with birds aggregating in the open grassland and wetland in Cat Tien. The density recorded in Yok Don was much lower than expected for the whole of the national park, given large extent of dry deciduous forest (see BirdLife International, 2001, Brickle, 2002 and Brickle et al., 1998) that was thought capable of sustaining a larger population. The habitat selection model suggested that the green peafowl mainly used areas close to water sources and that had a high coverage of undergrowth vegetation and few or no cattle. The lower density and drastic reduction of the green peafowl population in Yok Don might be a consequence of higher disturbance, through grazing, bushfires and poaching, than in Cat Tien. All of these were also observed during the survey.