Publications Archive

Observations of seabirds during two visits in the yacht Towrore to the southern extremity of South America in the summer and autumn of 1984 and 1985 are summarised with comments on their status in South America. Rockhopper and Macaroni Penguins (Eudyptes chrysocome and E. chrysolophus) are commoner than in the past, but larger penguins were not found breeding and may be more vulnerable since penguins still appear to be taken for bait. Chile holds about a sixth of the world’s breeding Black-browed Mollymawks (Diomedea melanophrys), a tenth of the Grey-headed Mollymawks (D. chrysostoma), many Blue Petrels (Halobaena caerulea) and Narrow-billed Prions (Pachvptila belcheri), and some Southern Giant Petrels (Macronectes giganteus). The White-chinned Petrel (Procellaria aequinoctialis) probably breeds, and possibly the Fairy Prion (Pachyptila turtur), collected in the past, and Antarctic Cormorant (Leucocarbo bransfieldensis). The first Manx Shearwaters (Puffinus puffinus) for Chile were also seen in the Magellan Strait and near Cape Horn.

This paper presents bird records from the Kingdom of Tonga which do not fit into other publications about the extensive field work of the Brehm Fund South Seas Expedition. Results of the first ornithological survey of the small island of ‘Eua’iki are presented. Most remarkably, this island has small numbers of Vini australis and Clytorhynchus vitiensis, which became extinct on ‘Eua and Tongatapu at the end of the 19th century. Other new distribution records for C. vitiensis are presented, and the record of its distribution in Tonga is revised. Its absence from the larger islands in southern Tonga is a result of human disturbance, most likely the introduction of Rattus rattus, while in the Vava’u group, competitive exclusion by Pachycephala jacquinoti may be the reason. Hirundo tahitica is now known from many locations. Breeding colonies seem to exist on Tofua and Nomuka, and a breeding population is probably establishing on ‘Eua. A few new data are added to the sparse knowledge about Pachycephala jacquinoti. Ardea novaehollandiae was recorded again from Tongatapu and Circus approximans for the first time from Tongatapu and Niuafo’ou. Records of Prosopeia tabuensis from Tongatapu and two of its offshore islands are given, and some remarkable changes in behaviour of Porphyrio porphyrio on small islands are reported. The brown female morph of Gallicolumba stairii, which has been known from Fiji and Samoa, is also in Tonga. An unidentified storm petrel has been seen close to Tongatapu. Breeding has been confirmed for Pterodroma nigripennis and Sterna sumatrana on several islands in the Tongatapu group. Some new breeding records for noddies (Anous spp.) on islands off Tongatapu are presented. Observations of Procelsterna cerulea on ‘Eua suggest that the species breeds in the cliffs of the east coast. Sterna anaetheta certainly breeds in cliffs on the southern coast of Tongatapu. The discovery of new breeding colonies of Pterodroma nigripennis supports the hypothesis that the species is extending its range. Blue-crowned Lorikeets and Fiji Shrikebills have been isolated on ‘Eua’iki for more than a century. These populations, and others, are very small (fewer than 100 birds each). Their size and long isolation call into question the concept of Minimum Viable Populations.

The distribution of Hutton’s Shearwater (Puffinus huttoni) in the Kaikoura ranges is restricted to the upper Kowhai River and Shearwater Stream catchments. Survey quadrats were established and colony boundaries mapped as baseline data for monitoring. The breeding population was estimated to be at most 134 400 pairs, less an unknown number of non-breeding pairs and unmated birds. Productivity in used burrows in the Kowhai River and Shearwater Stream catchments was estimated at 31% and 16% respectively. Numbers have declined since the 1880s. The species fits the IUCN category of ‘vulnerable’.

Early European naturalists and explorers, who of necessity spent much of their time near the coast, do not seem to have logged or noticed Caspian Terns. This notable species was not officially listed in New Zealand till about 1860. It was regarded as rather scarce throughout the 19th century and even well into the 20th century. Two possible explanations for this apparent scarcity are offered: (a) that, as it laid large palatable eggs in places that were usually accessible, it had become scarce after 800 years of hungry human (Polynesian) predation, and (b) that, like some other waterfowl, e.g. Pukeko, White-faced Heron, Royal Spoonbill, it is a comparative newcomer to New Zealand and has enjoyed a ‘boom period’ in the middle of the 20th century.