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Moults of rectrices and body plumage of blue-eyed and king shags (Phalacrocorax atriceps and P. albiventer) and phenology of moults

Notornis, 35 (2), 129-142

P.C. Rasmussen (1988)

Article Type: Paper

In blue-eyed and king shags (Phalacrocorax atriceps and P. albiventer), moult of the rectrices is irregular but not random. R1 (Rectrix 1) was usually the first to be replaced in sub-adult blue-eyed shags but not in adults. In blue-eyed shags, moulting rectrices were most often separated by one or two non-moulting rectrices. When two adjacent rectrices were moulting in adult blue-eyed shags, one was usually over half grown before the other began moulting, or both were about the same length or missing. Up to six rectrices moult simultaneously in sub-adults and up to eight in adults. Moult of rectrices is usually not symmetrical in blue-eyed shags. In adults, the number of moulting feathers and the number of waves are correlated among flight feathers. In flight feathers of sub-adults, the number of moulting feathers is not correlated but the number of moulting waves and the number of retained juvenile flight feathers are correlated. Most moult of flight and body feathers takes place after breeding, but a limited amount occurs during breeding and in winter.

Breeding of the banded dotterel, Charadrius bicinctus, on the Cass River Delta, Canterbury

Notornis, 35 (1), 9-14

M. Bomford (1988)

Article Type: Paper

Laying began in August, peaked in late September to early October and finished in December. Eggs were laid at intervals of three days to a normal clutch of three. The site and dimensions of 47 nests are described. The female did 82% of daytime incubating, and incubation averaged 26.5 days. Most eggs were lost to predators and only 44% hatched. In fine weather chicks made trips away from the nest within a few hours of hatching. Once hatching was completed the nest was deserted, but parents and chicks stayed in the territory until the chicks fledged at 5-6 weeks. Post-breeding flocks contained 23% juveniles.

Foraging by Adélie penguins during the incubation period

Notornis, 35 (1), 15-23

L.S. Davis; G.D. Ward; R.M.F.S. Sadleir (1988)

Article Type: Paper

Nine Adelie penguins (Pygoscelis adeliae), 4 females and 5 males, were tracked by radio telemetry when they went to sea from the Northern Rookery, Cape Bird, Antarctica, on their first foraging trips of the incubation period. Each penguin took a different direction on leaving the rookery but maintained its approximate heading, suggesting that it was navigating. Radio contact was lost after 2-12 days as birds moved beyond the 100 km radio horizon. The penguins spent about one-third of their time on ice floes. Most of their time in the water was spent diving and feeding. Dives (including underwater swimming) lasted for a mean of 92.5 s, followed by a mean recovery period of 33.8 s. The length of the recovery period was significantly correlated with the length of the dive. From the maximum dive times, the duration of “feeding” dives, and the dive: pause ratios, Adelie penguins seem to have diving abilities between those of the other two pygoscelid penguins, the gentoo and chinstrap. We hypothesize that the Adelie penguins may travel large distances from the rookery during the incubation period so as to forage on the larger and more pelagic krill, Euphausia superba.

The identity of the hakawai

Notornis, 34 (2), 95-116

C.M. Miskelly (1987)

Article Type: Paper

The hakawai was a ‘mystery bird’ formerly found on islands off Stewart Island; although never seen, its startling call was heard at night. The call of the hakawai, and its distribution and decline are described. The hakawai (under several spelling variations) is widely mentioned in myths and legends of the Maori throughout New Zealand; these records are summarised and the various theories for the hakawai’s identity are discussed. Evidence for non-vocal aerial displaying by New Zealand snipe (Coenocorypha) is presented. The hypothesis that the hakawai was an aerial display of Stewart Island snipe (C. aucklandica iredalei) was investigated by comparing the distribution and decline of snipe with that of the hakawai, and by playing a tape recording of an aerial display of Chatham Island snipe (C. pusilla) to people who had heard the hakawai. These data support the hakawai = snipe hypothesis. The historical distribution of Stewart Island snipe included Big South Cape, Pukeweka, Solomon, Pourama, Jacky Lee, Herekopare, Ruapuke and Green Islands in the last 100 years. The extinction of snipe on these islands is attributed to introductions of ship rats (Rattus rattus, two islands), weka (Gallirallus australis, four islands) and a combination of weka and cats (Felis catus, two islands). It is proposed that subfossil remains of Coenocorypha from the North Island and the South Island be referred to C. a. barrierensis Oliver 1955 and C. a. iredalei Rothschild 1921 respectively.

A colony of the little shag and the pied shag in which the plumage forms of the little shag freely interbreed

Notornis, 34 (1), 41-50

M.J. Taylor (1987)

Article Type: Paper

During the 1977-1985 period a colony of 80-120 little shags (Phalacrocorax melanoleucos brevirostris) was studied at Hobson Bay, Auckland City. The breeding season of little shags was from August to March or April. Pied shags (Phalacrocorax varius), which joined the colony during the study period and have tended to displace the smaller species, have nested throughout the year. For both species highest numbers of nesting pairs were present in spring (October-November). Little shags of the pied form constituted one-third of the colony and interbred freely with birds of the white-throated and smudgy plumages. Fledglings have either the pied or totally black plumage and both can occur within the same brood. Aspects of behaviour are described and a detailed account of the colony is given.

Swamp habitat use by spotless crakes and marsh crakes at Pukepuke Lagoon

Notornis, 34 (3), 207-216

G. Kaufmann (1987)

Article Type: Paper

A combination of searching for nests and responses to taped calls of spotless crakes (Porzana tabuensis) was used to determine habitat use by and abundance of spotless crakes and marsh crakes (P. pusilla). Spotless crakes preferred to nest in scattered to dense tussock sedge (Carex secta) with an overstorey of raupo (Typha orientalis). Responses to taped calls indicated that they may have also nested in dense flax (Phormium tenax) and dense raupo. Limited information on marsh crakes indicated that they nested in tussock sedge with little or no raupo overstorey.

Changes in gull numbers over 25 years and notes on other birds of the Otaki-Ohau coast

Notornis, 34 (4), 327-338

R.G. Powlesland; H.A. Robertson (1987)

Article Type: Paper

The number of black-backed gulls (Larus dominicanus) between the Otaki and Ohau Rivers, on the southwest coast of the North Island, has more than doubled in the last 25 years. There was a significantly larger proportion of subadults in 1961 than now, indicating that the population may have been in a growth phase in the early 1960s. The number of red-billed gulls (L. novaehollandiae) was about one-third of the 1961 level; this coincides with a sharp fall in the number of red-billed gulls nesting on nearby Kapiti Island. Numbers of other coastal birds were recorded and are discussed.

Genetics of polymorphism in the little shag

Notornis, 34 (1), 51-57

J.E. Dowding; M.J. Taylor (1987)

Article Type: Paper

A genetic model is presented to explain plumage polymorphism in the little shag (Phalacrocorax melanoleucos brevirostris). Parent-offspring data from an Auckland colony show that expression of the three morphs (white-throated, smudgy and pied) is primarily controlled by two alleles at a single genetic locus. The allele specifying ‘dark’ (D) shows incomplete dominance over that specifying ‘pied’ (6). Comparison of morph frequencies with calculated genotype frequencies reveals that about 40% of white-throated birds are homozygous dominant (DD), the rest of the white-throated birds and all smudgy birds are heterozygous (Dd), and pied birds are homozygous recessive (dd). The population mates non-assortively and the Hardy-Weinberg law correctly predicts the frequencies of black and pied offspring from crosses. Morph frequencies (and allele ratios) show a gradient from north to south in New Zealand, dark birds being more common in the south. The main factor maintaining this cline may be climatic.
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