Publications Archive

Radio-tagging of 54 New Zealand Pigeons (Hemiphaga novaeseelandiae) captured at Pelorus Bridge Scenic Reserve, Marlborough, showed that about half of the birds which fed there in spring on deciduous foliage moved away from the reserve from early summer onwards. They travelled 2-18 km to other areas of native forest. Most remained away for 2-9 months and at least some bred at their summer destinations. Individual birds tracked in different years provided strong evidence for their using traditional seasonal ranges, although the timing of movements varied between years, depending on fruiting phenology and breeding success. Some birds made up to three return movements from and back to Pelorus Bridge within a year, visiting different destinations in different seasons. Late summer and autumn movements were apparently linked to feeding on miro (Prumnopitys ferruginea) fruit. Five of 25 radio-tagged pigeons which moved to known destinations away from the reserve occupied areas of privately owned native forest during the breeding season.

The breeding and feeding of Kerguelen Terns (Sterna virgata) and Antarctic Terns (S. vittata) were studied at the Kerguelen Islands in January-February 1985. The laying period was estimated to have ended during the third week of December for Kerguelen Terns and started during the last week of December for Antarctic Terns. Kerguelen Terns used a wide variety of feeding techniques and fed in marine, freshwater and terrestrial habitats. Marine crustaceans, fish and terrestrial invertebrates were the main prey. Antarctic Terns fed only in marine habitats, where crustaceans were the main prey. Even when feeding close together, the terns were seldom aggressive. Contrary to previous reports, Kerguelen Terns fed fish to chicks and fledglings despite the presence of Antarctic Terns. Frequent strong winds prevail at the subantarctic islands, and so wind speed is probably the most important factor affecting the ecology of Kerguelen and Antarctic terns.

Growth curves were fitted to data collected by L.E. Richdale on Yellow- eyed Penguin (Megadyptes antipodes) chicks during three seasons in the 1930s, and compared statistically with curves fitted to data collected at the same locality over two seasons in the 1980s. Interseasonal variation also was compared across the five decades. Although the variation was similar, chicks from Richdale’s poorest season had higher fledging weights than chicks from two out of the three seasons monitored during the 1980s. Growth rates were significantly different for all comparisons except between the 1939-40 and 1983-84 seasons, with contemporary chicks tending to grow faster at 30 – 50 days of age, i.e. during the period of maximum growth. The slower growth of Richdale’s chicks during this period was not reflected in lower fledging weights. As growth rates are more likely to be affected by diet than by other factors, this difference may be due to a change in the availability or quality of prey items during the chick-rearing period, perhaps in response to long-term commercial fishing pressure in the area.

Behaviour of Kingfishers (Halcyon sancta vagans) was studied at three nests in Canterbury. Courtship feeding was observed. Chicks were fed by both parents, predominantly on lizards, crabs and insects. No difference was found in the proportion of prey sizes fed to chicks of different ages ((2=0.02, p>0.05). Chicks were fed about every 20 min in the first week, the rate increasing to every 10 min in the latter stages of nesting. Kingfishers were aggressive during nesting and attacked a wide variety of species as well as other Kingfishers. Mortality during nesting of adult Kingfishers was heavy in suburban habitats.

During a trip to Adams Island in the Aucklands group in November- December 1989, 5 Auckland Island Rails (Rallus pectoralis Muelleri) were caught and 43 heard calling. Several hundred rails are probably on Adams Island, where they are widespread in vegetation that provides good cover near ground level. They were not found on other islands in the Aucklands group, though they may occur on Disappointment Island, which was not visited. The calls of Auckland Island Rails are recognisably similar to those of the same species in Australia but easily distinguished from those of other Auckland Island bird species. During November and December rails readily responded to tape recordings of their own calls, and they called, both spontaneously and in response to tapes, throughout the daylight hours. Two nests were found, one active with two eggs and one old. Chicks were heard at two places. Auckland Island Rails probably lay in October and November, and their nests are built in thick vegetation dominated by tussocks and sedges. Auckland Island Rails seem consistently smaller than Lewin’s Rail (R. pectoralis) from south-eastern Australia, and their subspecific status is appropriate.