A previously unknown population of Coenocorypha snipe was discovered on Jacquemart Island, a rat-free 19 ha islet adjacent to Campbell Island in the New Zealand subantarctic, on 9 November 1997. This was the first evidence of Coenocorypha snipe occurring in the Campbell Island group, which is believed to have been infested by Norway rats (Rattus norvegicus) before the first naturalists visited in 1840. Rats were eradicated from 11,268 ha Campbell Island by the New Zealand Department of Conservation in July 2001. Two snipe were seen, and one caught, on Campbell Island adjacent to Jacquemart Island on 10 March 2005. The bird caught was a fully-feathered chick, indicating successful breeding on Campbell Island. The Campbell Island snipe remains undescribed and critically endangered.
Counts, mark-recapture estimates of abundance, and simulations were used to assess the population trends of Antipodean wandering albatross (Diomedea antipodensis) and Gibson’s wandering albatross (D. gibsoni). Estimates of population size based on mark-recapture analysis had much greater power to detect trends than did annual counts of nests. In fact, nest counts were so variable that significant trends would only be detected when populations had already changed by more than 25%. Population simulation models were constructed using survival and productivity data from the two species, and recruitment data from closely related species. The simulation models were sensitive to variation in recruitment data and suggested that the recruitment of Gibson’s wandering albatrosses is significantly lower than that of Antipodean wandering albatrosses. The sensitivity of the models to variation in the surrogate data compromises the usefulness of such models as predictive tools. After large, probably fisheries-induced declines during the 1970s and 1980s, Antipodean wandering albatross populations are now increasing at about 3.1% per annum, while Gibson’s wandering albatross populations are static.
New Zealand bellbirds (Anthornis melanura) disappeared suddenly from the northern New Zealand mainland and several large northern islands in the late 19th century. During the past 75 years, several unsuccessful attempts were made to reintroduce them. Between 1988 and 1991, four translocations (111 birds) were made to Waiheke Island near Auckland, sourced from Kaingaroa (21 birds) and Cuvier Island (90 birds). The birds were conspicuous immediately after release but became progressively less visible within six months and the translocations failed. While the cause(s) of failure are unknown, predation by mammalian predators, especially ship rats (Rattus rattus) is likely to have been a critical factor. Other possible reasons for failure of bellbird translocations are discussed, along with the reasons why original bellbird populations disappeared from northern New Zealand and subsequently failed to re-establish.
We observed black and white-plumaged storm petrels on 27 seabird-watching trips to the outer Hauraki Gulf, New Zealand, November 2003 – June 2005. We studied their plumage characteristics, behaviour and seasonal occurrence: the birds had common plumage characteristics and sightings of them were concentrated in the outer Hauraki Gulf from October to March and further offshore in April-May. Their presence in the Hauraki Gulf coincided with summer breeding of other seabirds, in particular white-faced storm petrels (Pelagodroma marina). Their pattern of occurrence off northern New Zealand suggests the birds may be breeding in the Hauraki Gulf; the Mokohinau Islands, rid of rats (Rattus exulans) 15 years ago, is a potential breeding site In our view these black and white storm petrels do not conform to descriptions of any extant species known from New Zealand waters, and, consequently, we speculate that our observations may have been of New Zealand storm petrels (Pealeornis maoriana Mathews 1932), a species known from only three specimens collected in the 19th century.
Recaptures of banded birds, and call counts, indicate a population of great spotted kiwi (Apteryx haastii) near Saxon Hut, Heaphy Track, in Kahurangi National Park has remained stable between 1987 and 2004. The number and the locations of occupied territories have changed little. Although few juveniles were encountered during searches with dogs, at least 10 of 22 territorial adults present in 1987 were replaced by a total of 12 birds over 17 years implying that recruitment kept pace with the annual adult mortality of about 4%. We suggest that the incidence of the main predators of kiwi (stoats, ferrets, cats and dogs) was low in this very wet area (rainfall >5500 mm/ year). Our findings support the current ‘Vulnerable’ conservation threat ranking for the species.
We experimentally evaluated the food hoarding behaviour of North Island robins (Petroica australis longipes) at Karori Wildlife Sanctuary, Wellington. Mealworms were offered to free-ranging pairs of male and female robins to evaluate whether their food hoarding behaviour was similar to previous observations of South Island robins. We also tested theoretical predictions derived in the Northern Hemisphere, which argue that competitively subordinate birds should hoard more food than dominant birds. Results showed that the food hoarding behaviour of North Island robins was similar to South Island robins, except that North Island robins repeatedly used the same cache sites, which is rare in South Island robins. Data did not support the prediction that competitively subordinate birds hoard more food than dominant birds. Males acquired most of the mealworms offered to birds during trials, and won nearly all aggressive interactions observed between sexes. Therefore, males appeared to be competitively dominant to females in winter. However, males stored over five times as many mealworms as females, which is opposite to theoretical predictions. We interpret the reluctance of females to cache food as a strategy to avoid food loss to competitively dominant males.
35,289 southern royal albatrosses (Diomedea epomophora) were banded on Campbell Island between 1941 and 1998, including 24,258 chicks and 11,031 adults. By 2003, 240 (0.68%) band recoveries and live recaptures away from Campbell Island had been reported. Birds banded as chicks were reported at a median age of 2 years (range 1-28 yrs), and adults at a median of 4 years after banding (range 0-27 yrs). The peak of band recoveries occurred close to the peak of banding in the late 1960s. Recoveries were generally made between latitudes 30-55°S in southern Australasia and South America; 43% were on coasts and 56% at sea. Birds recovered at sea (n = 134) were usually in waters over the continental shelf (up to c. 200 m deep water; 55% of records) or slope (200-1000 m; 19%). Distribution varied with age, with 56% of juveniles (<20 months old, n = 78) found on the west side of South America (especially in December – February), 54% of immature birds (<6 years old, n = 48) on the east side of South America (especially in June – July) and 55% of adults (≥ 6 years old, n = 114) in the New Zealand region. Most (94%, n = 102) birds recovered on the coast were dead, compared with 46% (n = 134) of those found at sea. Some birds were apparently caught to read bands, and 36% of the live birds (n = 78) were released without their bands, and of the remainder, 3 birds were seen again on Campbell Island. About half (49%, n = 61) of deaths at sea were caused by accidental capture on fishing lines. A possible decrease in the population during the 1970s – early 1980s coincided with the peak in long-line fishing in the New Zealand region and suggests this albatross could be affected by any new fisheries or intensification of fishing without adequate mitigation. It would be prudent to monitor the trends, dynamics and foraging of a range of New Zealand albatross species within an, as yet undeveloped, strategy for research and monitoring of seabirds in New Zealand.
The Australasian crested grebe (kamana: Podiceps cristatus australis) is nationally endangered within New Zealand. A census, conducted on 24 January 2004 by 81 observers, recorded 300 adults and estimated a further 15 as present on 41 of the 93 lakes counted. Assuming approximately 30 grebes to be present on lakes not counted, the national population of adult crested grebes is estimated to be 340-350. This is 40% higher than the population recorded in 1980. In addition, 75 juveniles were counted on 18 lakes. As in the 1980 survey, approximately 55% of the adult crested grebes were recorded on Canterbury lakes. A significant regional change has occurred with birds now present on lakes in Otago, absent from Nelson lakes, and in reduced numbers in Marlborough, North Canterbury, Westland and Fiordland. In addition, a significant decline has occurred at Lake Alexandrina, one of the strongholds identified in the 1980s. Forty percent of the present adult population was recorded on two lakes, Lake Heron and Lake Hayes. We identify priority sites where management to reverse declines could be implemented and we recommend a suite of management actions.
We studied activity rhythms at a gentoo penguin (Pygoscelis papua) colony at Cierva Point, Antarctic Peninsula, during the 1992-93 summer. We counted the number of penguins crossing a specific point on their route to and from the colony. Penguins showed a strong daily rhythm of activity, with a two-peak pattern for those leaving the colony and a one-peak pattern for those returning. The peak of penguins departing to sea was at dawn, with a secondary peak in the afternoon which was coincident with the peak of returns. Although this behaviour could be explained by nest relief schedules, the pattern remained once crèches had formed. The main peak of departures strongly correlated with sunrise, which might support the existence of a light signal synchronizing activity. Even though an external factor could be triggering movements, an endogenous circadian clock might drive both patterns.
Kaka (Nestor meridionalis), red-crowned parakeet (Cyanoramphus novaezelandiae), whitehead (Mohoua albicilla), tomtit (Petroica macrocephala), and bellbird (Anthornis melanura) have all recently been reintroduced to sites in or near Wellington city. Prior to or concurrent with these translocations, unmarked individuals of all five species were detected in forested reserves on Wellington peninsula. Based on the number of birds seen, and frequency of sightings, we suggest that red-crowned parakeets, whiteheads and bellbirds have established resident populations in some reserves independent of translocations. We attribute these successful re-establishments to the effective control of possums (Trichosurus vulpecula) and rats (Rattus sp.) undertaken by Greater Wellington Regional Council and the Department of Conservation.