Helmeted hornbills are Critically Endangered due to intensive hunting for their solid casques marketed as red ivory, with populations in terminal decline.
Hunting for casques involves shooting and killing individual birds for a single body part. The species is so rare that any hunting removes individuals with irreplaceable reproductive value. Forest loss removes the large territories they require. Their complex calls and behavioral ecology means the loss of experienced individuals harms the social fabric of remaining populations. The rate of decline is comparable to the most rapid vertebrate population crashes ever recorded.