Publications Archive

Observations of ducks on Macquarie Island in December 1985 and 1986 are summarised. Although the island has many wetlands, previous records suggest that ducks mainly use those within wet tussock grasslands in the lowland, coastal areas: recent observations confirm this. Reduced primary productivity on plateau wetlands may result in minimal secondary production of foods in a relatively harsh environment, one where nesting cover has been degraded by introduced rabbits and where predatory skuas are prevalent. Ducks, including hybrids between Grey Duck and the alien Mallard, used Square Lake and Duck Lagoon for feeding and resting, although their rate of feeding was higher at Square Lake. Broods were recorded only at Duck Lagoon, where Poa foliosa provides extensive cover. Introgression on Macquarie Island has occurred unsupported by local liberations, distant from human activity, and has implications for the gene pool of Grey Duck elsewhere.

Four surveys for Kokako were conducted in the Hunua Range between November 1986 and May 1988, by playing tapes of the local song dialect. Three of the four surveys were done in conjunction with the Auckland and South Auckland branches of the Ornithological Society of New Zealand. Forty Kokako were recorded, of which 12 were definitely in pairs, one was a definite juvenile and another a possible juvenile. Some of the remaining 26 were likely to have been paired. Thirty-eight birds were recorded in tawa-podocarp forest and two in adjacent second-growth scrub. The 40 birds ranged in altitude between 300 and 660 m ad. with an average of 490 m. They were distributed in the following catchments: Mangatangi (20 birds), Mangatawi (12), Orere (5), Tapapakanga (2) and Hauarahi (1). Most records were of birds heard rather than seen, and tape responses were low compared with those in surveys elsewhere. Comparisons are made with past surveys and survey techniques, and the discussion includes options for forest management in the Hunua Range.Ecology Division, DSZR, c/- Bulk Water Department, ARC, Private Bag, Auckland

The osteology of the New Zealand genera Mohoua and Finschia shows that they are definitely not referable to the Pachycephalinae or any other group within the corvine assemblage. This is in contrast to Sibley and Ahlquist’s original interpretation of their DNA-DNA hybridization studies and supports a recent reanalysis of that data by critics, who concluded that these genera belong among the “Passerida”. Within that group, the relationships of Finschia and Mohoua remain uncertain. No osteological basis could be found for continuing to separate the genus Finschia from Mohoua. The three species in the expanded genus Mohoua show increasing specialization for use of the hindlimb in foraging and in order of most primitive to most derived should be listed as M. novaeseelandiae, M. albicilla, and M. ochrocephala. The last two species are very distinct from one another osteologically and are not to be regarded as subspecies of a single species.

Australasian Bitterns (Botaurus stellaris poiciloptilus) were studied in the Whangamarino wetlands in the autumn and winter of 1986. A seasonal difference in the time of feeding was noted, as well as a local movement to feeding grounds. A decrease in the number of birds seen in the study area in winter seemed to be related to the duck hunting season and high water levels. A mixture of water purslane and willow weed on a wet substrate was the preferred habitat. “Surveillance posture” seems a better description of the traditional “freeze” behaviour. The birds gave this response even when there was no apparent danger.

New anatomical evidence shows that New Zealand’s extinct Stephens Island wren (Traversia lyalli Rothschild, 1894) had a much reduced wing skeleton, short, rounded, soft-quilled wings and an almost acarinate sternum. It was therefore the only known completely flightless passerine.

The stomach contents of 50 adult Fiordland Crested Penguins (Eudyptes pachyrhynchus) were collected during the post-guard phase of chick growth. Twenty-two food species were identified from 19 families.  The composition of the diet, expressed as percentages of calculated weight, was 85% cephalopods, 1304 crustaceans and 2% fish. The sexes did not differ in their diets. The cephalopods and fish were juvenile and larval forms, indicating that the penguins were feeding on pelagic macro-zooplankton and micro-nekton. The main cephalopod taken was Nototodarus sp., and so the penguins were foraging mainly over the continental shelf, which extends no more than 10-15 km from the shore.