The number of calling birds observed in 2013 at Yok Don National Park was compared with the observations made by
Brickle et al. (1998). The areas surveyed in the two years did not overlap entirely with the area surveyed by Brickle et al.
(1998) because of changes to the forest as a result of human settlement. In 2013, therefore, we sought to cover as much
of Yok Don National Park as possible. For practical purposes, we divided the green peafowl population into three sectors
separated by Yok Don and Chu Minh Mountains (Fig. 1b). In 1998 there were 13 point count observations and in 2013 there
were 15 line transects. All transects in 1998 and 2013 covered the south, center and north of Yok Don National Park. For
further detailed comparison, we sought to compare the mean number of calling birds in 2013 with the data provided by
Brickle et al. (1998) for each of these three sectors.
The only previous quantitative assessment of green peafowl numbers in Cat Tien National Park was provided by Robson
et al. (1991: see also Robson et al., 1993), who reported 17 calling birds in 13 km2. They gave no details of survey method or