Publications Archive

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.

Between 1987 and 1996, 2,383 Wrybills (Anarhynchus frontalis) were banded on their wintering grounds at two locations near Auckland; 690 of these were recaptured on 830 occasions. Birds started to arrive at their wintering grounds in December; and stayed at the more northern location until April, when they moved to wintering sites further south. First year birds comprised

The Westland Petrel (Procellaria westlandica) population is thought to have increased significantly in recent decades, perhaps as a result of increased food in the form of waste from fishing vessels. A survey of Westland Petrels off the West Coast of the South Island, New Zealand, showed that fishing vessels in the West Coast South Island Hoki (Macruronus novaezelandiae) fishery influence the distribution of Westland Petrels, but only a small proportion of the Westland Petrel population appears to utilise this fishery waste at any one time. Westland Petrels appear to select foraging areas primarily on natural features, such as water depth, and only if fishing vessels are in the same area are Westland Petrels attracted to them.

A list of all historical specimens of the New Zealand Laughing Owl (Sceloglaux albifacies Gray, 1844) known from museums around the world is presented. There are 52 feathered specimens (24 mounts, 28 study skins), 2 alcohol specimens, 3 part skeletons, and 17 eggs. Of the recorded specimens, only two specimens are identified that could be the type of S. rufifacies Buller, 1904, but whether it is one of these is unknown. Two unlocalised specimens in the Cambridge University Museum are tentatively identified as coming from Buller’s second bird collection.

Eighteen sub-adult and five adult North Island Weka (Gallirallus australis greyi) were found dead on Kawau Island in the Hauraki Gulf, between 7 March and 20 April 1996. Weka initially collapsed losing leg control, and died within two days. All dead birds had ample fat reserves. No common cause of death was found in seven autopsies. No long term impact on the population is predicted.

Six nest sites of New Zealand Falcon (Falco novaeseelandiae) breeding in a mixed podocarp hardwood forest are described. All nest scrapes were located in Collospermum hastatum epiphytes on emergent. Nest height was about twice the height of the surrounding canopy. All but one nest trees were alive and appeared to be in good health. The large diameter (mean at breast height: 105 cm) and the height of nest trees (mean 36 m) indicated that falcons selected older trees in the forest. Nests tended to be located mid- slope or towards a gully and of northerly aspect. Management of New Zealand falcon habitats should involve the maintenance of adequate emergent trees in forests, from which falcons can select appropriate nest sites.

The body composition of ten adult and five juvenile Knots (Calidris canutus rogersi) in the migratory period from Northland, New Zealand, was studied. Basic physical measurements of all individuals are provided. Adults were heavier than juveniles, but showed a large variation in mass – some were at estimated departure mass while others apparently were only in the early stages of mass increase, allowing an investigation of changes during the “fattening” procedure. Changes in fat-free dry tissue (protein) of organs were complicated, with pectoralis and heart muscles increasing with total fat mass, while intestine and stomach mass decreased. This resulted in total fat-free dry tissue firstly increasing with fat mass, then levelling off or decreasing. This reallocation of protein is interpreted as being a method of freeing up muscle protein for redeposition in other organs during premigratory fuelling. Most fat was deposited subcutaneously, apparently in a linear fashion. In contrast, abdominal fat showed proportionately higher masses as total fat increased, while fat around other organs showed the reverse pattern. Adults were significantly larger than juveniles in ten organ comparisons, but only four of these were clearly related to migration. Organ sizes in C. c. rogersi were much smaller than in the European-wintering C. c. islandica, and slightly smaller than African-wintering C. c. canutus. Salt gland mass of C. c. rogersi in this sample from New Zealand was much larger than that known from European birds, which may reflect migratory preparation. Lean mass was estimated at around 109 g.

The Chatham Island Pigeon or Parea (Hemiphaga novaeseelandiae chathamensis), is the endangered subspecies, endemic to the Chatham Islands, of the New Zealand Pigeon or Kereru (H. n. novaeseelandiae). During the early period of European and Maori settlement, 1820s to 1870s, Parea were common on Chatham, Pitt and Mangere Islands, but by 1990 the population possibly comprised fewer than 50 birds, mostly in forest habitats of the southern part of Chatham Island. Between 1989 and 1994, the numbers of feral cats and brushtail possums (Trichosurus vulpecula) were reduced in areas occupied by Parea in the Awatotara and Tuku Valleys of south-western Chatham Island The adult Parea population of these valleys increased three-fold from 27 in 1990 to 81 in 1994. The long-term future of the Parea is dependent on the exclusion of cattle, pigs and sheep from forest reserves. Keeping cat and possum numbers at low levels in Parea habitat on Chatham Island, and the establishment of a population on Pitt Island once cats have been removed from one or more of its reserves.

Wetland birds on 11 rivers of the Upper Waitaki Basin, South Island, New Zealand were surveyed annually between 1991 – 1994. Diversity, minimum abundance and density of birds were compared. In total 26 species of wetland birds were recorded. Minimum estimated river bird numbers were: 3566 Black-backed Gulls (Larus dominicanus), 3302 Black-fronted Terns (Sterna albostriata), 3260 Banded Dotterels (Charadrius bicinctus), 793 Black-billed Gulls (Larus bulleri), 789 Wrybills (Anarhynchus frontalis), 788 South Island Pied Oystercatchers (Haematopus ostralegus), 421 Pied Stilts (Himantopus himantopus), 85 Black Stilts (Himantopus novaezelandiae), 51 Caspian Terns (Hydroprogne caspia), and 3680 waterfowl and cormorants. Densities of birds ranged from 0.17 birds ha-1 on the Pukaki River to 0.95 birds ha-1 on the Lower Ohau River. The Cass, Lower Ohau, Godley, Tekapo and Ahuriri Rivers had higher densities of one or more species than the Upper Ohau and/or Pukaki Rivers. Densities of Black-fronted Terns, Black Stilts, Pied Stilts and Caspian Terns were negatively correlated with altitude, and in general birds preferred river sections with low or moderate flows, and low or moderate vegetation cover. Eight of the 11 rivers surveyed had more than 1% of estimated total populations of one or more of three globally vulnerable or endangered species, and in combination rivers of the Upper Waitaki Basin support almost all known Black Stilts, 15% of all Wrybills and 32% of all Black-fronted Terns. We suggest that the Upper Waitaki Basin may now provide half of all remaining suitable braided river bird habitat in New Zealand.