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
Résumé
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.