Population Density Estimation of Hornbills in the Eastern Part of Huai Kha Khaeng Wildlife Sanctuary, Thailand

Hornbills belong to the Bucerotidae Family, and almost all species within this family are vulnerable to extinction. This study examined the population density of four hornbill species in the eastern part of the rainforest of the Huai Kha Khaeng Wildlife Sanctuary. The species studied were the Great Hornbill (Buceros bicornis Linnaeus 1758), Rufous-necked Hornbill (Aceros nipalensis Hodgson 1829), Wreathed Hornbill (Rhyticeros undulates Shaw 1811), and Tickell’s Brown Hornbill (Anorrhinus tickelli Blyth 1855). Moreover, the study investigated factors influencing hornbill density using distance sampling with point transect methods, as well as the unmarked package in R. The survey was conducted along four 9-km survey lines, covering a total of 36 km, using 45 survey points with 200-m spacing between points. In total, 180 points were surveyed, with each point observed for 10 min. The study was replicated twice, covering an area of approximately 600 km2, with surveys conducted from November 2023 to January 2024, and again from March 2024 to October 2024. The results showed the following hornbill population densities (individuals/km2): Great Hornbill 10.16±0.07 (n=108), Rufous-necked Hornbill 5.95±0.07 (n=74), Tickell’s Brown Hornbill 4.42±0.03 (n=61), and Wreathed Hornbill 1.52±0.01 (n=22). Factors that significantly influenced hornbill density included elevation, slope, average precipitation, average temperature, and montane forest. These findings contribute to the understanding of hornbill ecology and population dynamics. The results can guide management strategies and promote public awareness of habitat conservation.