Publications Archive

Osteological characters distinguishing the South Georgian Diving Petrel (Pelecanoides georgicus) from the Common Diving Petrel (P. urinatrix) are described. P. georgicus is shown to be the main diving petrel in Holocene fossil deposits at Mason Bay, Stewart Island, New Zealand, where it is represented by thousands of bones. P georgicus is also recorded from dune deposits on Chatham Island. The Codfish Island population is thus a remnant of a formerly large Pacific population that bred on Macquarie Island, Auckland Islands, Stewart Island and Chatham Island, and is therefore of high conservation priority.

The North Island Weka (Gallirallus australis greyi) population at Parekura Bay was monitored in 1991-95, during a long dry El Nino event. Adult Weka had declined from ~400, in February 1987 (Beauchamp 1988), to 47-63 Weka in Parekura Bay and Whangamumu areas in June 1991. By March 1995 there were only three Weka left there. Enhanced production of young Weka was insufficient to prevent decline. Known mortality factors were road kills, Timms traps and dogs and stoats. Throughout the study the population lacked females. A “crowing call” by males was identified as associated with mate loss and mate finding.

We examined digestive tract contents and stable nitrogen isotope ratios (15N) in breast muscles of Buller’s Shearwaters (Puffinus bulleri) salvaged from squid and large- mesh driftnets in the central North Pacific Ocean. The epipelagic Pacific Saury (Cololabis saira) was the predominant prey, making up 71% of prey mass in digestive tracts. The remainder of the diet included small numbers of crustaceans, small fishes, and squids. The high degree of specialization in the diet seems to indicate that in the North Pacific, Buller’s Shearwaters usually feed at or near the water surface and rarely pursue food under water. Although these birds have been observed feeding on scraps from fishing vessels, our data suggest that offal comprises less than 10 percent of the diet. Stable nitrogen isotope values provided quantified information on the timing of arrival of migrants into the North Pacific.

A breeding male Chatham Island Taiko (Pterodroma magentae) was found recently dead of injuries by its burrow on 14 November 1996. Intraspecific fighting followed by sepsis of wounds seems the likely cause of death. All parts were preserved. Food items of Taiko include four squid species and one fish species. Its intestinal structure suggests a close relationship with the P. mollis group and P. macroptera. Measurements of bones indicate that most subfossil bones previously referred to this species were correctly identified.

Twenty species of birds are recorded from Kapingamarangi Atoll, southern Micronesia, 14 sea- and shorebirds and six land birds. Eleven are documented or probable breeders or former breeders. The Micronesian Starling (Aplonis opaca) is the only native, resident land bird, and it is common and widespread, averaging 5.7 birds ha-1 atoll-wide among the 31 islands. A kingfisher is reported from Kapingamarangi for the first time, and a recently collected specimen of Shining Cuckoo (Chysococcyx lucidus) is the first record for Micronesia and first report of the nominate (New Zealand) subspecies north of the Bismark Archipelago.

Avifaunas from Pleistocene and Holocene fossil deposits in the Hodges Creek Cave System in northwest Nelson, New Zealand, are described. At least 20 species of birds are present in glacial-age deposits from these sites at about 900 m above sea level. A sample of 12,000 year old Finsch’s Duck (Euryanas finschi) bones shows that post-glacial shortening of the wings in this species had already started at that time.

Densities of the North Island Weka (Gallirallus australis greyi) have declined over much of the East Cape region since 1985. The area around Motu township had densities exceeding 0.72 ha-1 in 1985-86, but they disappeared by 1990 and have increased only marginally since. The decline coincided with floods and the spread of ferrets (Mustela furo) into the valley. The only region where Weka density increased is in the hills between Motu and Opotiki Counts in the Toatoa and Whitikau Valleys in 1995 found a maximum density of 0.60 adult Weka ha-1 in mixed farmland and fern, and between 0.08 – 0.18 ha-1 in mature forest. There are less than 1,000 adults in the centre of this region, and in some areas the population is male-dominated.