New data on elevational distribution, abundance and nesting of birds on Bougainville Island, Papua New Guinea

Bougainville is a mountainous tropical island in Melanesia, reaching 2,712 m at Mt. Balbi, the highest elevation in the tropical South Pacific outside of New Guinea. In 1972, J. Diamond climbed the active stratovolcano to c.2,000 m and provided detailed information on its montane avifauna. Fifty years later, the elevational distribution of birds on Mt. Balbi was resurveyed in November 2022, this time to the summit. Twenty-nine of the 37 bird species for which Diamond had provided elevation data were found at higher elevations than 50 years ago. In total, 35 species were found at new max. elevations.