Pelagic birds around Rapa and Marotiri, French Polynesia, October–December 2019, with notes on Rapa Shearwater Puffinus myrtae and Titan Storm Petrel Fregetta [grallaria] titan

Abstract

We report pelagic observations from around Rapa Island and Marotiri Rocks, in the Austral Islands, French Polynesia, made during the first dedicated at-sea survey of birds in the region, during October–December 2019. We recommend that the regional occurrence of several seabird species be modified and that the list of avifauna for Rapa and Marotiri, the Austral Islands, and East Polynesia variously be amended to include Juan Fernández Petrel Pterodroma externa, Mottled Petrel P. inexpectata, Gould's Petrel P. leucoptera, Stejneger's Petrel P. longirostris, Buller's Shearwater Ardenna bulleri and Arctic Skua Stercorarius parasiticus. Two Gould's Petrels were behaving as if breeding, and the timing of egg laying by Christmas Shearwater Puffinus nativitatis is apparently somewhat earlier than the species' other populations. We found Polynesian Storm Petrel Nesofregetta fuliginosa foraging in large numbers around Marotiri suggesting a hitherto unrecognised and perhaps significant breeding population; we also found large numbers around Rapa. Titan Storm Petrel foraged off Rapa in substantial numbers and c.5% appeared to be a variant, raising the possibility of two distinctive phenotypes. We include at-sea images and a field description of ‘classic’ Rapa Shearwater Puffinus myrtae, and report an unidentified small Puffinus seen at Marotiri. Our survey adds significant new information to knowledge of seabirds in this region, and in combination with previous work argues strongly for the conservation of Rapa, Marotiri and the surrounding ocean’s pelagic birds.