Fifty-three captive-bred New Zealand shore plover (Thinornis novaeseelandiae) were released on Motuora Island in the Hauraki Gulf, New Zealand in an attempt to establish a second population of this endangered shorebird in the wild. The birds were liberated in four releases between September 1994 and February 1997. In September 1997, eight (15%) of the released birds were still resident on Motuora Island. Dispersal to the mainland was the principal known cause of loss of birds from the island, with predation being the next most important cause. Differences were found between the use of adult and juvenile birds for release but there did not seem to be any difference between using hand- or parent-reared birds. Possible seasonal patterns of disappearance may become clearer once more birds have been released on the island. Recommendations for future management and research include continuing the transfer programme to Motuora Island with intensive monitoring during the first month after release, inclusion of more adult birds in releases, release of both hand- and parent-reared captive birds and conducting more research into morepork predation of shore plover.
The diet of the morepork (Ninox novaeseelandiae) in New Zealand was investigated by analysing stomach contents. In the sample of 75 stomachs from throughout New Zealand, 1696 prey items were identified, 98% of them invertebrates. Major invertebrate prey taken included Lepidoptera, Coleoptera, and Orthoptera. Lepidoptera were consumed mostly in summer and Coleoptera in winter. Vertebrate prey were predominantly birds, but included one house mouse (Mus musculus). New dietary items included praying mantis (Dictyoptera), blowflies (Diptera), wasps (Hymenoptera), and slaters (Isopoda). Most prey was 20-50 mm in body length. Diets of male and female moreporks were similar, as were those of North and South Island birds. As suggested from other studies, the diet of moreporks is varied, but consists primarily of invertebrates. Food habits apparently reflect the seasonal abundance of prey.
Thirty-one species of wader have been counted on the Manukau Harbour and Firth of Thames in summer and winter censuses since the winter of 1960. Data are presented on total numbers of waders, the numbers of selected wader species and the numbers of observers involved in the counts. The numbers of many native waders have increased during the last 39 years, especially pied oystercatchers (Haematopus ostralegus), which have increased 8-fold from the 1960s to 1990s; however, pied stilts have been stable and wrybills (Anarhynchus frontalis) may be declining. Numbers of many Arctic wader species have increased on one or both harbours, but of the two main species, bar-tailed godwits (Limosa lapponica) have remained constant over both harbours and lesser knots (Calidris canutus) have declined slightly on the Firth of Thames but increased greatly on the Manukau Harbour. Notable changes of habitat are noted and possible reasons for changes in abundance of some species are discussed. Likely seasonal maxima of wader numbers are considered and the implications of these are discussed.
The breeding biology of the North Island tomtit (Petroica macrocephala toitoi) was studied at two sites in Pureora Forest Park, central North Island, during the 1997/98 season, and compared with data from the Ornithological Society of New Zealand’s Nest Record Scheme. The nesting season at Pureora was from 26 September 1997 to 15-17 February 1998, one pair fledging three broods. Of 11 Pureora nests and 32 of the Nest Record Scheme, 63.6% and 28.1% respectively were among dead hanging fronds of tree ferns, and 18.2% and 34.5% respectively were in holes in trees, rocks, banks, the ground or in nest boxes. The mean height of 11 nests at Pureora was 3.4 m, and that of 34 nests in the Nest Record Scheme was 2.8 m. Mean clutch size for the combined data was 4.15 eggs (n= 13). On all occasions, except one, females were incubating, with males feeding their mates at regular intervals. Both parents fed the chicks but only the female brooded them. Mean brood size at Pureora was 4.0 (n=4), but for the Nest Record card data it was 3.1 (n= 2 1). All 13 fledglings in four broods appeared to reach independence. Of 11 nesting attempts at Pureora, 72.7% were successful, compared with 45.4% of 11 attempts on Nest Record cards. This greater success at Pureora compared with other mainland areas was attributed to aerial 1080 possum control at Pureora reducing mammalian predator densities to low levels, and so reducing the incidence of predation.
The diurnal and seasonal attendance of kea (Nestor notabilis) at Halpin Creek dump, Arthur’s Pass, from April 1996 to March 1997 was investigated. Many more male (n=56) than female (n=4) kea were banded at the dump. Resighting data suggested that certain adult male kea habitually foraged at the dump, whereas younger male kea probably foraged at the dump until they dispersed from the dump in their second summer. The time individual kea spent at the dump varied considerably within and between seasons, but did not depend on the individual’s age. More kea were observed at the dump in winter than in summer and they spent more time at the dump in the winter than in summer.
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 (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’.