This study shows that the Red-tailed Tropicbird (Phaethon rubricauda) has a gradual clinal increase in the intensity of the rose-pink suffusion, egg size, culmen length and wing length in breeding populations between Kure Atoll in the northern Pacific and the Kermandec Islands in the southern Pacific. The illusion that birds from this cline comprise three subspecies has long been accepted because the large range of latitude that each subspecies had been arbitrarily given resulted in significant differences in mean measurements. However, as neither the northern rothschildi nor the southern roseotincta are clearly separable from melanorhynchos in the centre of the cline, they must all be one subspecies. Because the mean measurements of the nominate “subspecies” are nor significantly different from those of birds from
similar latitudes in the Pacific cline, or from westralis in the eastern Indian Ocean, there is no valid reason for distinguishing any subspecies in the Red-tailed Tropicbird.
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.