The rufous-necked hornbill (RNH; Aceros nipalensis [Hodgson, 1829]) is one of thirteen hornbill species
found in Thailand and is listed as vulnerable under IUCN Red List. The rufous-necked hornbill has been
locally extinct from most of its original habitat in northern Thailand mainly due to habitat loss and
fragmentation. The objective of this research was to estimate the density of rufous-necked hornbills in an
evergreen forest patch at Thung Yai Naresuan (East) Wildlife Sanctuary located in the core area of the
Western Forest Complex, Thailand. Density point counts along five trails were conducted to estimate
population density in 2007 and 2008. A total of 75 observations of rufous-necked hornbills were recorded
during field surveys. The average density was 5.55 individuals/km2, which was ranked as medium density
compared to Huai Kha Khaeng and Thung Yai Naresuan (West) Wildlife Sanctuary.