Publications Archive

In 1990-91, a previously unknown population of the Polynesian Ground Dove was discovered on Rangiroa Atoll in the Tuamotu Is, eastern Polynesia. This apparently isolated population was estimated at only 12-20 birds.

In October-November 1990, Chatham Island Pigeons (Hemiphaga novaeseelandiae chathamensis) in the Tuku a tamatea and Awatotara Valleys, Chatham Island, preferred plants characteristic of mixed broadleaf forest over plants typical of tarahinau forest. Mixed broadleaf forest is confined to gullies and valleys in the region. Browsing by cattle, sheep, pigs and possums is rapidly degenerating these forest remnants. Conservation of Chatham Island Pigeon depends on the protection of these remnants.

The Black-toed Petrel of Latham, on which Gmelin founded his Procellaria melanopus, has not previously been satisfactorily identified. For many years earlier this century, melanopus Gmelin was widely used as the name for the Providence Petrel Pterodroma solandri. On the basis of available evidence it is reasonable to conclude that Latham’s Black-toed Petrel was in fact a specimen of the Mottled Petrel Pterodroma inexpectata, taken in the course of Cook’s third voyage at sea off the north-west coast of North America, probably in the Gulf of Alaska in May 1778.

Aquatic invertebrates were extracted and identified from seven Blue Duck faeces collected from the Tongariro River in December 1990. A total of 927 aquatic invertebrates representing 37 taxa was identified. Over all samples, 45% of the aquatic invertebrates extracted were Chironornidae (samples ranging from 19-76%), 28% Trichoptera (ranging 11-49%), and 16% Ephemeroptera (ranging 2-42%). The dominant chironomid was Eukiefferiella sp., although Cricotopus spp. were also relatively abundant in some samples. Cased caddisflies were the main Trichoptera in all samples, but no one taxon was consistently dominant. Plecoptera comprised 0-20% of invertebrates in the faeces. In most samples collected below Tree Trunk Gorge, chironomids comprised ~61% of individuals recorded in the faeces, whereas above the gorge they comprised ~40% in any sample. Overall, the diet of Blue Duck on the Tongariro River in December 1990 was variable in terms of the proportions of species and the number of invertebrates that were consumed. This has also been shown in studies of Blue Duck diet on other rivers.

Preserved material from two Kakapo (Strigops habroptilus), two Kea (Nestor notabilis) and two Kaka (Nestor meridionalis) was dissected. A fledgling Kakapo had short, stout mandibles, a wide, thick tongue and a thick pharyngeal pad. The lower mandible closed against both the rostra1 end of the hard palate and the underside of the free end of the tongue. The crop was well defined. In the fledgling and in the headless body of an adult Kakapo a fusiform proventriculus was followed immediately by an approximately spherical, uniformly muscular gizzard. There were five main intestinal loops and no evidence of a vitelline diverticulum or of caeca. In Kea and Kaka the upper mandible was longer, the tongue (especially in Kaka) was narrower and fimbriated, and the crop was similar to that of the Kakapo. The mandibles, tongue and palate of the Kakapo appear to be particularly well adapted for the grinding of fibrous plant tissues to extract soft portions and juices.

From 13 to 21 August 1992, we surveyed Breaksea and adjacent islands, Chalky and Preservation Inlets, and some of the coastline north of Chalky Inlet, for Fiordland Crested Penguins. Minimum total counts were 215 nests and 425 birds on Breaksea and adjacent islands, and 59 nests and 108 birds in Chalky and Preservation Inlets. Most nests on Breaksea and adjacent islands were under vegetation. Further south, nests were both in caves and under vegetation. Many apparently suitable caves did not contain penguins. The total absence of penguins from the outer coast reinforces our belief that we are finding most of the colonies in the survey area.

The previous distribution of the Shore Plover (Thinornis novaeseelandiae) and the possible reasons for its decline are outlined. The species is now confined to one small population on South East Island (Rangatira) in the Chatham Islands. In January and February 1993, we captured and banded or re-banded about 95% of this population and determined its age structure. Excluding juveniles of the 1992-93 season, 55% of the population is aged 6 years or less, 31% is aged between 7 and 12 years, and 14% is aged 13 years or more. The oldest bird currently alive is 18 years old. Estimates of population size and productivity for the season are compared with previous (mostly unpublished) records. Morphometric data are presented; there are small but significant differences in total head length, bill and tarsus between adult males and females, and in weight, wing and mid-toe between adults and 1-year-olds. In January, primary moult was more advanced in 1-year-olds than in adults.