Publications Archive

During a visit to North Brother Island in Cook Strait from 11 October to 6 November 1990, we estimated by quadrat sampling that the 4 ha island supported 1000 pairs of Fairy Prions, 600 pairs of Common Diving Petrels, and 225 adult tuatara. Most Diving Petrels nested below Coprosma scrub, and a few eggs were laid on the surface under dense shrubs. Many prion burrows were in more open vegetation. Burrows of both species were simple and were not shared with tuatara. Some evidence of tuatara preying on unattended eggs was found, but there was no evidence that the endemic Sphenodon guntheri, which is smaller than S. punctatus, fed on adults of either species. Many Diving Petrels, prions, Fluttering Shearwaters and Red-billed Gulls fed in tide rips close to the island. The position of each species in feeding assemblages was related to their dive depths. Diving Petrels in areas of strong currents submerged for only a few seconds at a time, but in areas of calm water dive durations averaged 29 seconds.

Pipit (Anthus novaeseelandiae) numbers on nine count routes in the Wellington region ranged from 0.16 to 6.22 per km on average. Estimated densities in regions with some favourable habitat varied between 1.0 and 2.5 per square kilometre. Highest numbers were in the hills south and west of Karori, and on the southern and western beaches between Owhiro Bay and Titahi Bay. Densities were lower over the rest of the region due to intensive farming, unfavourable plant succession pathways to bush, and urban development.

On Ewing Island, Auckland Islands, during the austral summer of 1991-92, Auckland Island Teal Anas aucklandica aucklandica were dispersed principally as pairs occupying and vigorously defending small all-purpose territories. Most territories were around the margins of the island, either within a narrow fringe of grassland, or at the very edge of Olearia lyallii forest with access to boulder beaches or low wave platforms. Few territorial pairs lived entirely within the forest. A small number of juveniles and unpaired adults assembled as a flock at one protected coastal location where food was super-abundant, but other unpaired birds appeared to live furtively around the margins of occupied territories. Some non-territorial pairs persistently tried to occupy sections of shoreline in the face of defence by territorial pairs. Only territorial pairs were observed breeding. Females sited their nests on the ground well hidden from view above and laid eggs each of which weighed, on average, 14.8% of body mass. Mean clutch size in 45 nests was 3.4 eggs and hatching success of 86 eggs was 93%. Ducklings were first seen on 11 December and most broods had been reduced to a singleton within eight days of hatching. The probability of a duckling surviving from hatching to 30 days was 0.272. The estimated mean size of extant broods at fledging was 1.6. By estimation, only 14% of ducklings may survive to fledging, and up to two-thirds of all breeding pairs may fail to raise any young. Re-laying by unsuccessful pairs may extend the breeding season into April. Males contributed fully to care of the brood but were not always seen in close attendance. By comparison with other related Australasian teals, Auckland Island Teal have a more terrestrial lifestyle and show more enduring territoriality.

Foraging flights of three female Auckland Island Wandering Albatross (Diomedea exulans gibsoni) were tracked from Adam Island in the Aucklands group by satellite radio telemetry. Two of the birds were incubating eggs, while the third was in the early stages of chick raising. All three birds made long flights of 11-13 days and 1000 – 1500 km into the Tasman Sea. The chick-rearing female also made shorter flights of less than 4 days and 900 km. The distances covered were similar to those recorded for other Wandering Albatross subspecies, but foraging strategies differed. Auckland Island birds initially flew fairly directly and at high speed, then seemed to slow down and change direction more frequently for a few days, before flying directly back to the Auckland Islands. Two explanations are suggested: birds may have been “commuting” to favoured foraging areas, or were blown by the winds. Speeds reached during the “commuting” phase were similar to those recorded for D. e. chionoptera, but were slower at other times. The Tasman Sea between latitudes 45°S and 40°S is an important foraging area for some female Wandering Albatross breeding on Adam Island.

Five surveys for the North Island Kokako were carried out in the Hunua Range, Auckland between October 1992 and March 1994. Twenty six-28 Kokako were recorded, including 3 possibly 4 pairs. Results suggest that there has been a decline in Kokako numbers since the previous survey in 1986-1988. All Kokako were recorded in tawa-podocarp forest. The birds ranged in altitude between 320m and 640m. Birds were distributed in the following catchments: Mangatangi (13 birds), Mangatawhiri (12 birds), Orere (2 birds), Tapapakanga (1 bird). Nearly all records (65%) were of birds heard rather than seen. Two pairs were seen.

During two weeks on the south-west Pacific islands of Wallis and Futuna in September-October 1993 I notes 24 of the 35 species of birds recorded by French ornithologists during a fuller survey in December 1985 and January 1986. A count of boobies on Futuna showed that 5% were adult Brown Boobies. Of the remainder, 27% were adult white morph Red-footed Boobies and 54% were adult Red-footed Boobies of the “white-tailed brown” morph. The continued presence of good numbers of Blue-crowned Lories on Futuna may indicate a lack of ship rats.

We review 16 published and 17 previously unpublished accounts of the nesting of North Island Kokako (Callaeas cinerea wilsoni) recorded between 1880 – 1989. Nests were on average 8.5 m above ground, in many different tree species, but usually with dense overhead cover. Kokako laid eggs from October to February. The modal clutch had three eggs or young, four nests had two. Only the female built the nest, incubated, and brooded young, though the male fed the female at or near the nest throughout the nesting period. Incubation took about 18 days and fledging about 31 days. We suggest that several aspects of Kokako nesting evolved in response to diurnal avian predation, and that these behaviours give ineffective protection against nocturnal, arboreal, introduced mammal predators.

During 1976-89, 490 Black Shag (Phalacrocorax carbo) nestlings were banded at Matthews and Boggy Pond wildlife reserves, and Te Hopai Lagoon, Wairarapa. Forty-one (8.4%) have been recovered, all dead, 20 of unknown causes. Of 21 for which the cause of death was known, 13 drowned in set nets, 11 of these birds being less than 6 months old. Six shags had been shot, all prior to 1986 when the Black Shag received partial protection. While 85% of the shags were found within a 100 km of the banding sites, mainly to the north and west, one bird was recovered about 2000 km away on Lord Howe Island.