Publications Archive

Long-tailed cuckoos (Eudynamys taitensis) were studied on Little Barrier Island during three summers. The only species of host was the whitehead (Mohoua albicilla). Rates of brood parasitism on the island were 18.1% overall, 35.7% at altitudes above 250 m, and 5.4% at altitudes below 250 m. The breeding season for cuckoos probably lasted for 4-6 weeks from mid-November, suggesting that early nests of the whitehead escaped brood parasitism. The available information suggests that the major hosts of the cuckoo are the whitehead, the yellowhead, and possibly the brown creeper, although other hosts are used occasionally. As adult cuckoos call in small groups during the breeding season, I speculate that long-tailed cuckoos may have a lek-type social organisation.

Intraspecific variation in morphometrics, plumage colouration, moult and breeding is described and its taxonomic significance assessed. There is a latitudinal cline in morphometrics and colouration among mainland, nearshore island, and Auckland Is populations. Southern bellbirds are larger and more brightly coloured, but they have shorter bills. Intensity and hue of the iridescent head and olive-green plumage colouration are determined by the degree of melanism, which increases southward and on all isolated islands but the Three Kings. Age and sex differences in plumage colouration are also caused by the different degrees of melanism. The degree of melanism may be reduced by the dryness of the environment, particularly in the period before moult. Overlain on this cline are insular trends in morphometrics, colouration, moult, and breeding pattern. Bellbirds, particularly males, from isolated islands are larger than those on the mainland, whereas clutches are fewer and smaller, and breeding seasons and adult moult earlier. The size increase occurs whether other species of honeyeater are present or not and may result from high densities and the increased tendency of males and females to use different feeding niches. The relative body proportions of island populations vary and wing length does not increase as rapidly as body size. A new subspecies is described from the Poor Knights Is. It is characterised by a distinctly blue rather than violet iridescent head in males, an immature plumage phase, and other differences in size, relative proportions, breeding, and time of moult. The nomenclature and taxonomic status of other island subspecies and of the extinct Northland bellbird A. dumerilii are reviewed. A. dumerilii and A. incoronata are regarded as synonyms of A.m. melanura.

The pair bonding, recognition, defence, and courtship displays of the red-footed cormorant (Phalacrocorax gaimardi) are described for the first time. Similarity in displays reinforces van Tets’ contention that this species is a member of the Stictocarbo group. Its closest relatives seem to be the spotted shags of New Zealand waters and the European shag. The Atlantic population of the red-footed cormorant is small and isolated, and it may differ from the much larger population along the Pacific coast by various behavioural and ecological features.