Bangladesh (B), Bhutan (B), Brunei Darussalam (B), Cambodia (B), India (B), Indonesia (B), Laos (B), Malaysia (B), Myanmar (B), Thailand (B), Vietnam (B).
Southern Bhutan and north-eastern India east to Vietnam (northern Annam), and south to Sumatra, Borneo, Java and Bali, including several intervening offshore islands.
 
Population
Estimated population is unknown (2010).
Voice
A loud, raucous, grunting 'uk-guk', the first note being softer and lower-pitched than the second, repeated every 1 - 2 s. Also very loud whooshing wingflaps.
Wreathed Hornbill (Rhyticeros undulatus) [XC169450]
by Mike Nelson from Seribu Riam, Murung Raya, Central Kalimantan, Indonesia (wingbeats)
Wreathed Hornbill (Rhyticeros undulatus) [XC21653]
by Mike Nelson from Sungai Wain Protection Forest, East Kalimantan, Borneo, Indonesia (call, calls, wingbeats)
Nest
In a hollow of a large tree, 18 - 26 m above the ground. The same cavity may be used year after year.
Eggs (Guide)
1 - 3; white. Incubation: by female. Female is sealed into the nest cavity.
Subspecies
Genus sometimes merged with Aceros. Has in past sometimes been treated as conspecific with Plain-pouched Hornbill (Rhyticeros subruficollis). Northern mainland population described as subspecies ticehursti on basis of larger size, and smaller Bornean birds as aequabilis, but variation apparently clinal and racial separation unwarranted.
No subspecies.
Similar Species
Wrinkled Hornbill (Rhabdotorrhinus corrugatus) which is smaller, has a more colorful face pattern and has black at the base of the tail.
References
See References.