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 (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 km-2 and 10 ind. km-2, respectively. Foraging behaviours used by pipit differed significantly between rough fernland, 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.
In 1960, a census of the spotted shag (Stictocarbo punctatus punctatus) population on Banks Peninsula found 9,787 breeding pairs (Turbott & Bell 1995). Here we report the results of a comparative census conducted on Banks Peninsula during the 1996 breeding season. Thirty-six years after the original census, the number of breeding pairs was found to have more than doubled to 22,123 pairs. We speculate that the population was formerly limited by food availability and that a reduction in fishing effort around Banks Peninsula, especially in the late 1980s, may have contributed to the observed growth in the shag breeding population.
During 1995, participants in the Beach Patrol Scheme patrolled 3,498 km of the New Zealand coastline. There were 7,625 dead seabirds of 55 species recovered by patrollers. In addition, beach patrollers found 156 birds of 28 non-seabird species. Unusual finds were the third specimen of a beach-wrecked lesser frigatebird (Fregata ariel) in New Zealand and five Kermadec petrels (Pterodroma neglecta). Australasian gannets (Morus serrator) wrecked in larger numbers than in any year since the start of the Beach Patrol Scheme. There were 648 birds recovered at an average rate of 22.2 birds per 100 km. A large wreck of sooty shearwaters (Puffinus griseus) occurred on Stewart Island in May 1995. Causes of seabird mortality are discussed in the paper.