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.
Eighteen sub-adult and five adult North Island Weka (Gallirallus australis greyi) were found dead on Kawau Island in the Hauraki Gulf, between 7 March and 20 April 1996. Weka initially collapsed losing leg control, and died within two days. All dead birds had ample fat reserves. No common cause of death was found in seven autopsies. No long term impact on the population is predicted.
Six nest sites of New Zealand Falcon (Falco novaeseelandiae) breeding in a mixed podocarp hardwood forest are described. All nest scrapes were located in Collospermum hastatum epiphytes on emergent. Nest height was about twice the height of the surrounding canopy. All but one nest trees were alive and appeared to be in good health. The large diameter (mean at breast height: 105 cm) and the height of nest trees (mean 36 m) indicated that falcons selected older trees in the forest. Nests tended to be located mid- slope or towards a gully and of northerly aspect. Management of New Zealand falcon habitats should involve the maintenance of adequate emergent trees in forests, from which falcons can select appropriate nest sites.
The body composition of ten adult and five juvenile Knots (Calidris canutus rogersi) in the migratory period from Northland, New Zealand, was studied. Basic physical measurements of all individuals are provided. Adults were heavier than juveniles, but showed a large variation in mass – some were at estimated departure mass while others apparently were only in the early stages of mass increase, allowing an investigation of changes during the “fattening” procedure. Changes in fat-free dry tissue (protein) of organs were complicated, with pectoralis and heart muscles increasing with total fat mass, while intestine and stomach mass decreased. This resulted in total fat-free dry tissue firstly increasing with fat mass, then levelling off or decreasing. This reallocation of protein is interpreted as being a method of freeing up muscle protein for redeposition in other organs during premigratory fuelling. Most fat was deposited subcutaneously, apparently in a linear fashion. In contrast, abdominal fat showed proportionately higher masses as total fat increased, while fat around other organs showed the reverse pattern. Adults were significantly larger than juveniles in ten organ comparisons, but only four of these were clearly related to migration. Organ sizes in C. c. rogersi were much smaller than in the European-wintering C. c. islandica, and slightly smaller than African-wintering C. c. canutus. Salt gland mass of C. c. rogersi in this sample from New Zealand was much larger than that known from European birds, which may reflect migratory preparation. Lean mass was estimated at around 109 g.
The Chatham Island Pigeon or Parea (Hemiphaga novaeseelandiae chathamensis), is the endangered subspecies, endemic to the Chatham Islands, of the New Zealand Pigeon or Kereru (H. n. novaeseelandiae). During the early period of European and Maori settlement, 1820s to 1870s, Parea were common on Chatham, Pitt and Mangere Islands, but by 1990 the population possibly comprised fewer than 50 birds, mostly in forest habitats of the southern part of Chatham Island. Between 1989 and 1994, the numbers of feral cats and brushtail possums (Trichosurus vulpecula) were reduced in areas occupied by Parea in the Awatotara and Tuku Valleys of south-western Chatham Island The adult Parea population of these valleys increased three-fold from 27 in 1990 to 81 in 1994. The long-term future of the Parea is dependent on the exclusion of cattle, pigs and sheep from forest reserves. Keeping cat and possum numbers at low levels in Parea habitat on Chatham Island, and the establishment of a population on Pitt Island once cats have been removed from one or more of its reserves.
Wetland birds on 11 rivers of the Upper Waitaki Basin, South Island, New Zealand were surveyed annually between 1991 – 1994. Diversity, minimum abundance and density of birds were compared. In total 26 species of wetland birds were recorded. Minimum estimated river bird numbers were: 3566 Black-backed Gulls (Larus dominicanus), 3302 Black-fronted Terns (Sterna albostriata), 3260 Banded Dotterels (Charadrius bicinctus), 793 Black-billed Gulls (Larus bulleri), 789 Wrybills (Anarhynchus frontalis), 788 South Island Pied Oystercatchers (Haematopus ostralegus), 421 Pied Stilts (Himantopus himantopus), 85 Black Stilts (Himantopus novaezelandiae), 51 Caspian Terns (Hydroprogne caspia), and 3680 waterfowl and cormorants. Densities of birds ranged from 0.17 birds ha-1 on the Pukaki River to 0.95 birds ha-1 on the Lower Ohau River. The Cass, Lower Ohau, Godley, Tekapo and Ahuriri Rivers had higher densities of one or more species than the Upper Ohau and/or Pukaki Rivers. Densities of Black-fronted Terns, Black Stilts, Pied Stilts and Caspian Terns were negatively correlated with altitude, and in general birds preferred river sections with low or moderate flows, and low or moderate vegetation cover. Eight of the 11 rivers surveyed had more than 1% of estimated total populations of one or more of three globally vulnerable or endangered species, and in combination rivers of the Upper Waitaki Basin support almost all known Black Stilts, 15% of all Wrybills and 32% of all Black-fronted Terns. We suggest that the Upper Waitaki Basin may now provide half of all remaining suitable braided river bird habitat in New Zealand.
The establishment since 1984 of small of Takahe (Porphyrio mantelli) on four predator-free islands has been an important component of the conservation strategy for the birds. However, initial productivity of birds in these habitats has been lower than expected due largely to low hatching success of early clutches. This study aims to describe behaviour associated with courtship, incubation and post-hatch care to assess possible behavioural causes of low productivity in Takahe on islands. No unusual behaviour associated with breeding was observed that might result in low productivity, although only two complete copulations were observed during the study. One incomplete copulation involving a yearling male was also observed. Territorial behaviour was recorded to compare with later years when densities of island populations increase. Six territorial interactions between neighbouring pairs were observed, three when pairs were between nesting attempts and ranging widely, and three when two pairs nested in close proximity. Monitoring of aggressive behaviour may be important as it may interfere with successful reproduction.
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.
The rare reversed sexual bill dimorphism of the extinct New Zealand endemic bird species, the Huia (Heteralocha acutirostris: Callaeidae) occurs in two Australian riflebird (Ptiloris) and three New Guinea sicklebill (Epimachus [Drepanornis]) birds of paradise (Paradisaeidae). While less extreme than that of the Huia, the female bill length proportionate to tarsus length is 7-18% longer than in males. In this proportionate bill length, females are longer-billed than males in most typical (polygynous) birds of paradise. More marked examples of reversed sexual hill dimorphism in the Paradisaeidae occur in species with greater proportions of wood-dwelling arthropods in their diets. Ecological studies of these species might provide insights into the way Huia lived and how their bill dimorphism evolved.