Notes on breeding and conservation of birds on Niuafo'ou Island, Kingdom of Tonga

Abstract

Niuafo'ou lies very isolated in the Pacific, is well forested and not densely populated by humans. These facts as well as the lack of larger rat species make it a refuge for birds rare elsewhere in the region. This paper covers all 17 breeding species and gives breeding data for 14 of them, collected from October 1991 to December 1992. Ten species had a well-defined breeding season of 2?7 months somewhere between September and April, which often differed from other adjacent islands: Audubon's Shearwater Puffinus Iherminieri, Pacific Black Duck Anas superciliosa, Banded Rail Rallus phillippensis, Spotless Crake Porzana tabuensis, Purple Swamphen Porphyrio porphyrio, Barn Owl Tyto alba, Red-vented Bulbul Pycnonotus cafer, Polynesian Starling Aplonis tabuensis nesiotes, and Jungle Myna Acridotheres fuscus. The Blue-crowned Lorikeet Vini australis nested in October, November and July. It did not only breed in tree hollows, but also inside a rotten log on the ground. Other observations suggest that it visits ground holes as well, either for nesting or resting. A breeding colony of Audubon's Shearwater is the first one confirmed for Tonga. Four species nested in the wet and dry season: White-tailed Tropicbird Phaethon lepturus, Pacific Reef-heron Egretta sacra, Pacific Pigeon Ducula pacifica and Polynesian Megapode Megapodius pritchardii. Since September to March is the main breeding season for birds on Niuafo'ou, it is proposed that hunting and egg collecting, both important parts of the local tradition, are restricted to the other months of the year. In case of the endangered Polynesian Megapode we suggest a restriction of egg collecting and propose a translocation programme to another island. Additionally, we suggest that the islets in the crater lake become protected as they are free of feral cats, and some birds occur in higher densities there. Niuafo'ou also deserves attention as resting place for six vagrant and migrant species; large numbers of Wedge-tailed Shearwaters Puffinus pacificus are hunted when they visit between October and June.