The endemic brush-turkey of Waigeo Island in eastern Indonesia, Aepypodius bruijnii, is revealed to nest only on the island's previously ornithologically unexplored highest summits, along an ecological gradient above 620 m elevation where a structurally distinctive, windsheared and possibly locally edaphically controlled, stunted cloud-forest thrives on infertile substrates. The species is confirmed to breed at two locations only, and the known population totals 47 mound-owning males or 84 mature individuals. Its global population is estimated at 349 mound-owning males or 977 mature individuals, primarily confined to 60 km2 of cloudforest habitat spread over six locations, with 98% of the population restricted to just three locations in the eastern part of the island. Details are provided on the bird's altitudinal distribution, habitat preferences, spatio-temporal use of incubation sites, population densities, locations and incidental lowland records. Threats that impinge on the species are discussed in depth, and it is concluded that its current precautionary treatment as Vulnerable warrants upgrading to Endangered in accordance with the revised IUCN Red List categories and criteria. Habitat destruction as a consequence of wild fires and a recent logging epidemic is identified as the major factor threatening this unique brush-turkey's long-term survival.