Differences in the time of onset of breeding, morphology, egg size, plumage and vocalisations of dark-rumped petrels (Pterodroma phaeopygia phaeopygia) were investigated on four islands in the Galapagos. Comparisons were made with P. p. sandwichensis in Hawaii. In Galapagos, breeding cycles differed among islands, and on San Cristobal there were two populations that bred at different times. On Floreana, colonies at different altitudes bred at different times. Eggs were laid on Santiago over four consecutive months; on Santa Cruz the egg-laying period was shorter. Analyses of morphological measurements and notional volume separated Galapagos dark-rumped petrels into three groups. Birds on Santa Cruz and those breeding in the middle of the year on San Cristobal were the smallest; birds on Santiago and those breeding at the end of the year on San Cristobal were of intermediate size; and those on Floreana were the largest. There was a similar size trend in the breadth and volume of eggs. No relationship was found between variable plumage patterns on head and chest or between plumage and island populations. Evidence is presented that supports sexual dimorphism in vocalisations, and it is suggested that males make Sweet calls and females make Coarse calls. There were statistically significant interisland differences among Sweet calls and among Coarse calls. Dialects probably exist within the archipelago. Calls had either one or two introductory syllables. When present, the second introductory syllable was very similar to the single introductory syllable, and these may serve the same function. Discriminant analysis of Sweet calls correctly classified 82.296 of these into island of origin. A similar analysis of morphology correctly classified 58.6% of birds from five populations. A theoretical combination of these two analyses indicates a potential classification rate of 92.6%. Although there are differences among Galapagos populations, there is not yet sufficient evidence to warrant subspecific status. Vocalisations of the Hawaiian birds were quite different from those in Galapagos, and Galapagos birds were bigger. Dark-rumped petrels in Galapagos and Hawaii might be more distant taxonomically than currently recognised and they may be different species.
The Adélie penguin and Antarctic skua breed at Cape Bird, and nine other species have been recorded as visitors (emperor penguin, chinstrap penguin, southern giant petrel, Antarctic fulmar, Antarctic petrel, snow petrel, Wilson’s storm petrel, southern great skua, and southern black-backed gull). Fewer birds were recorded as visitors at Cape Bird than have been recorded at Capes Crozier and Royds, possibly because Cape Bird gets less wind.
The results of monitoring changes in cattle egret numbers in New Zealand and eastern Australia, recovery records for long-distance movements of marked birds from colonies in eastern Australia, and records for wing-tagged and colour-banded birds in the Hunter Valley of NSW indicate that a pattern of movement from the colonies occurs in waves in a south to south-easterly direction to Victoria, Tasmania and New Zealand during autumn and a return in spring. This movement can be described as migration. Although there is some circumstantial evidence, there is no confirmation that the same birds travel the same routes to the same destination each year. In the wintering areas they tend to restrict their activities to well-defined local territories. Significant numbers of birds remain in their natal area, however, where they may move relatively little, restricting foraging to a very limited local area for long periods, or be somewhat nomadic within a restricted region.
Post-moult dispersal of paradise shelducks (Tadorna variegata) in the Wanganui district was examined during 1987 and 1988 from hunting season band recoveries. Birds were banded at five locations, two coastal (Lakes Waipu and Marahau) and three hill country (Kakatahi, Parihauhau, and Mangamahu). Birds banded at different sites dispersed differently, with birds banded at the two coastal sites and Parihauhau more dispersive than those banded at Kakatahi and Mangamahu. Males dispersed more widely than females. Band recoveries were clustered into two separate groups, those from Kakatahi and Mangamahu, and a group comprising birds banded at coastal moulting sites and at Parihauhau. Coastal areas accounted for more than 70% of the hunting effort in the 1987 and 1988 hunting seasons, and it is suggested that the two groups of moulting birds be managed as separate population units.