New Britain in the Bismarck Archipelago of Papua New Guinea supports 14 endemic bird species and together with New Ireland, forms an Endemic Bird Area that supports 38 restricted range species. Extensive conversion of lowland forest to oil palm plantations resulted in the loss of over 20% of forest under 100 m altitude between 1989 and 2000. However the rate of loss has subsequently slowed (2.2% loss across all altitudes between 2002 and 2014), and much forest remains at higher altitudes: 72% of New Britain remained forested (including secondary forest) in 2014. Despite the ongoing high threat and rich endemic bird fauna, the state of knowledge of the conservation status of birds in New Britain is very poor. We use an unprecedented dataset based on 415 hours of bird surveys conducted in oil palm plantations, as well as primary and secondary forests at all altitudes, to revise the IUCN status of New Britain’s birds. These data indicate that six species of elevated conservation concern are less dependent on old-growth forest than previously assessed. We recommend reduced population size estimates for one species, New Britain Kingfisher Todiramphus albonotatus. We recommend increased population size estimates for seven species: Pied Cuckoo-dove Reinwardtoena browni, Yellowish Imperial Pigeon Ducula subflavescens, Green-fronted Hanging Parrot Loriculus tener, Blue-eyed Cockatoo Cacatua opthalmica, Violaceous Coucal Centropus violaceous, New Britain Boobook Ninox odiosa and New Britain Thrush Zoothera talaseae. Despite our comprehensive surveys, Slaty-backed Goshawk Accipiter luteoschistaceus, New Britain Sparrowhawk Accipiter brachyurus, New Britain Bronzewing Henicophaps foersteri and Golden Masked-owl Tyto aurantia remain very rarely recorded and require further assessment. With ongoing habitat loss, particularly in lowland areas, New Britain’s birds urgently require more attention.