Compared to the outlying mountain ranges of New Guinea and surrounding islands, the known avifauna of Yapen Island numbers fewer upland species than expected, perhaps reflecting reduced coverage by ornithologists. In particular, the eastern portion of Yapen's uplands remained ornithologically unexplored until September 2019, when a seven-day expedition reached an elevation of 1,315 m, and documented three new species for the island. Two (Black-eared Catbird Ailuroedus melanotis and Yellow-legged Flyrobin Kempiella griseoceps) are widespread across the other outlying ranges and were therefore expected to occur on Yapen, whereas the third (Dimorphic Jewel-babbler Ptilorrhoa geislerorum) concerns a presumably isolated population of a species otherwise known from south-east New Guinea.