Publications Archive

The archaeological and fossil avifauna of Niue Island in the southwest Pacific is described from ten sites. Fourteen species of birds, including an extinct species each of Gallirallus and Nycticorax, and an extirpated megapode (Megapodius pritchardii) were found. This increases the number of taxa known for the Niue fauna to 15 resident species, but faunas from surrounding islands indicate this is almost certainly an under-estimate of original diversity.

Wrybill (Anarhynchus frontalis) and Banded Dotterel (Charadrius bicinctus) are territorial birds which breed on braided riverbeds in Canterbury, New Zealand. Home ranges of Wrybill pairs were bigger than those of Banded Dotterel pairs on the Rakaia and Ashley Rivers. For Wrybill there were no significant differences in home range size between years and rivers, but home ranges of Banded Dotterel pairs were larger on the Rakaia R. than on the Ashley R. Wrybill home range size on the Rakaia R. was related to the presence of preferred minor channel feeding habitats; small home ranges contained mostly minor channels and large home ranges contained mostly major channels. The larger home ranges for Banded Dotterel on the Rakaia R. is thought to be related to greater habitat instability compared to the Ashley R. If large scale diversion of water occurs from these rivers then flows need to be managed so that the characteristics of the natural flow regime are maintained.

Natal philopatry of 859 Southern Buller’s Mollymawks (Diomedea bulleri bulleri) banded as chicks on North East Island, The Snares (48″02’S, 166″36’E), during August 1972 was investigated during 1977 to 1998. Eighty-six birds were recaptured as breeders; 57 of these were recorded within 100 m of their natal nest area and 29 dispersed over distances ranging from 100 m to 2430 m. The gender of 32 birds was determined by measurements of minimum bill depth and tarsus width, or by their behaviour. Of 17 males, 15 were found breeding within 100 m of their natal site and the remaining two birds dispersed 100 – 200 m. Of the 15 females, five were breeding within 100 m of their natal site and the remainder had dispersed 100 – 1640 m.

Caspian Terns (Sterna caspia) from an isolated colony in southern New Zealand were studied for 30 years. Aims of the study were to identify the birds’ wintering grounds and to discover the whereabouts of birds during immaturity, by tracing movements of known-aged birds. Adults moved to several wintering grounds up to 1150 km to the northeast. Some birds were locally nomadic in winter, but little distance nomadism was identified in adults. In some families, one parent left the colony up to three weeks before the rest of the family. Juveniles left their natal colony when aged 7–9 weeks, and each was accompanied by one parent until aged 8–9 months. Typically, parents took turns at accompanying a juvenile, in stints of ca. 1-3 days, but two siblings wintered 360 km apart, each accompanied by a parent. Birds on outward passage moved in stages in flocks of 2–4 birds. Families lingered at staging areas for 2-26 days. A 49–54 day old juvenile moved 195 km in five days. Mortality was high in juveniles which moved further than ca. 900 km. Seventy seven percent of juveniles remained sedentary at their wintering ground to age 9 months, and 30% stayed on at the same location through their second winter. Immature birds remained sedentary, were locally nomadic or wandered far inland. Some returned to the colony and stayed briefly, but those which had wandered tended to remain at one site for weeks or months before moving on. Juveniles begged only from their parents. Flight skills and some feeding behaviour of known-aged juveniles are described, as are some behaviours at staging areas.

Aerial surveys for flying seabirds were directed up to 18.3 km offshore from Banks Peninsula during February and July-August 1996. The abundance of Hutton’s/Fluttering Shearwaters (Puffinus huttoni/P. gavia) increased offshore, consistent with possible offshore increases in pelagic versus benthic productivity The decrease in abundance offshore of Spotted/Pied Shags (Stictocarbo punctatus/Phalacrocorax varius), Black- backed Gulls (Larus dominicanus), White-fronted Terns (Sterna striata), and Red-billed/ Black-billed Gulls Gull (L. novaehollandiae/L. bulleri) probably reflects their commuting to and from breeding and roosting sites. Hutton’s/Fluttering Shearwaters and White- fronted Terns were most common around the area east of Banks Peninsula. The distribution of other species around Banks Peninsula probably reflects breeding site distribution (Spotted Shags), and feeding opportunities on land (Black-backed Gulls). Convergent fronts were distributed around Banks Peninsula, and decreased in number offshore. Internal waves were most common toward the eastern end of Banks Peninsula, and were evenly distributed offshore. While the onshore-offshore distribution of the non- procellariiform species matched that of convergent fronts, seabirds and individual convergent fronts did not significantly co-occur.

Uncertainty still surrounds the status of the Orange-fronted Parakeet, Cyanoramphus malherbi. Doubts first raised in 1974 that it was merely a colour morph of the much more common Yellow-crowned Parakeet, C. auriceps, were supported by a morphometric study of museum specimens in 1981, and the results of cross-breeding experiments with wild-caught and aviary birds in 1986. Subsequently, the Orange-fronted Parakeet was deleted from the most recent Checklist of the Birds of New Zealand. However, some researchers and conservation managers remain unconvinced, because of doubts raised by electrophoresis of blood proteins, and claimed differences in the orange-fronted bird’s size, behaviour and ecology. This paper reviews the topic, discusses the evidence and arguments in the species versus colour morph controversy, and supports the view that the 2 forms are colour morphs of a single species.

We present population size estimates of mollymawk species at Bollons Island in the Antipodes group based on counts in 1994 and 1995. Totals of 115 pairs of Black-browed Mollymawks Diomedea m. melanophrys and about 20 pairs of White-capped Mollymawks D. cauta steadi were estimated to be nesting. Based on previous counts from Bollons Island and population estimates from other islands in the New Zealand region, we conclude that numbers of D. m. melanophrys have increased in this region, in contrast to D. m. impavida which has decreased. The few data on the population size of D. cauta steadi hint at a population increase in that taxon also.

The densities of Chatham Island Pipits (Anthus novaeseelandiae chathamensis) and Skylarks (Alauda arvensis) on the south coast of Chatham Island were estimated at 7 individuals km2 and 10 ind. km2, respectively. Foraging behaviours used by Pipit differed significantly between rough fenland, pasture and beaches. Foraging behaviours also differed significantly between Pipits and Skylark on pasture, and Pipits moved on average 10 times further per minute than Skylark. The make-up of Pipit foraging behaviour on fields and beaches on Chatham Island also differed significantly from those at Wellington, North Island, during autumn.

The breeding biology of Kakerori, or Rarotonga Flycatcher, (Pomarea dimidiata) was studied during ten years (1987-97) of experimental management aimed at saving this endangered monarch flycatcher from extinction. Kakerori remained territorial all year and were usually monogamous. Most birds kept the same mate from year to year, but pairs that failed to raise any young were more likely to divorce than successful pairs. Despite living in the tropics, Kakerori breeding was strictly seasonal, with eggs laid from early October to mid-February, and mostly in late October and early November. Nesting started earlier in years when October was very sunny. Most pairs (74%) laid only one clutch, but some pairs laid up to four replacement clutches when nests failed. Three pairs (1%) successfully raised two broods in a season. Rat (Rattus spp.) predation was the principal cause of nest failure, especially of nests in pua (Fagraea berteriana), the main fruiting tree used by rats during the Kakerori breeding season. Annual breeding productivity was initially poor (0.46 fledglings per breeding pair over two years) and the population was declining, but intensive management since 1989 has led to a great increase in productivity (1.07 fledglings per breeding pair over eight years) and the number of Kakerori has increased from 29 birds in 1989 to a minimum of 153 birds in 1997. Their IUCN conservation status can therefore be lowered from ‘critically endangered’ to ‘endangered’.

Weka (Gallirallus australis) can be aged accurately up until 50 days old using leg and bill measurements, and then less accurately up to 180 days old using plumage development, wing spur shape and iris colour. Weka less than one year old can be distinguished by their remex tip and wing spur shape. Beyond one year, Weka can only be placed into age groups, using wing spur shape.