Colony attendance and behaviour of non-breeding Buller’s albatrosses (Thalassarche bulleri) were studied at 2 Snares Is colonies in 2000-2004. Non-breeders comprised 31-32% of birds ashore in Mar-May (incubation to early chick-rearing), 44% in Jul (late chick-rearing), and 51% overall. Among non-breeders, the proportion of adults that had been recorded breeding in previous years decreased from 47% in Mar to 4% in Jul, with prebreeders (known-age birds that had not been observed breeding) dominating the composition overall (80%). The percentage of surviving birds seen ashore was 59% among prebreeders aged 6 years (modal age of first return), 88% among experienced prebreeders (birds that had been recorded ashore in >1 breeding season), 86% among remating (widowed or divorced) adults, and 63% among sabbatical (birds that had been recorded breeding in previous years, but were not breeding in the year of observation) adults. Colony attendance period was shortest among inexperienced prebreeders (latest birds to arrive), longest among 3rd year (i.e. known-age birds recorded ashore for the 3rd year) prebreeders (early arrival, late departure), and intermediate among last-time prebreeders and former breeders (early arrival, departure in mid-season). Failed breeders attended for up to 3 months, but departed after May irrespective of failure date. Birds stayed ashore for longer and at sea for shorter periods as they gained experience; the percentage of days ashore increased up to the 3rd prebreeding year, and was higher in males than females. Movements between colonies and subcolonies were most frequent during the first 3 prebreeding years. Prebreeders frequently joined display groups during their first 2 years (34% of observations in May), and associated with a nest site in May-Jul of their 3rd year. Among remating adults, displaying was most frequent in females and early in the season (Mar); their behaviour converged towards that of paired adults by May. Attendance patterns and behaviour were broadly similar to those of other albatrosses, except for earlier departure during the last prebreeding year not previously reported in an annually breeding species.
Sixteen of 26 hand-reared kakapo chicks (62%) have been successfully returned to the wild. These chicks were initially kept in thermostatically-controlled brooders, then in plastic tubs in an air-conditioned room, and finally a pen in an unheated room prior to transfer to an outdoor pen and release in the wild. Brooding temperature was progressively reduced to simulate the progressively longer period kakapo chicks spend in the nest without brooding. Humidity was maintained at 80% to simulate that measured in kakapo nests. Some chicks fed a relatively high fat diet within their first 20 days after hatching developed fatty liver disease; subsequently, chicks less than 45 days of age were fed a lower fat diet and older chicks gradually converted to a higher fat diet. Normal gut flora was successfully established in chicks by adding small quantities of adult kakapo faeces that had been screened for diseases and parasites. The growth rate of hand-reared chicks was significantly slower than that of parent-reared chicks during the first 40 days after hatching but there was no significant difference in growth rate in older chicks. Half the disparity in the growth rates of hand-reared and parent-reared chicks was due to the fact that most hand-reared chicks were suffering from ill health or injury before being taken into captivity. Two male chicks reared in isolation from other kakapo display varying degrees of sexual attraction to humans. The only sexually mature hand-reared female chick has mated and hatched a chick in the wild. Hand-reared kakapo comprised 40% of all chicks fledged since 1990 and presently comprise 20% of the total population of 86 birds.
Satellite telemetry was used between 1994 and 2004 to identify the distribution of 2 closely-related species of wandering albatross, Gibson’s (Diomedea gibsoni) and Antipodean (D. antipodensis), which breed in the New Zealand subantarctic. Trials of methods of attaching transmitters revealed that harnessed transmitters decreased foraging efficiency and increased mortality, whereas transmitters glued or taped on birds had little effect. There was some overlap in the species foraging ranges, but D. gibsoni mostly foraged in the Tasman Sea and D. antipodensis in the Pacific Ocean east of New Zealand. For both species the range of non-breeding birds was larger than that of breeders, but the core areas used by both breeders and non-breeders were similar. Non-breeding male D. antipodensis had the largest range, foraging off the coast of Chile, Antarctica and in the tropical South Pacific. In comparison, the range of D. gibsoni was small, with non-breeding male and female birds foraging westward to the south-eastern Indian Ocean but avoiding Antarctic waters. Individuals of both species and all stages of maturity had preferred but large foraging areas which lasted many years. Some seasonal trends in distribution were found. Both species preferred to forage at the outer edge of shelves and over seamounts, particularly where there were strong currents or eddies and productivity was enhanced, as well as over deep water. Over the past 40 years, longline fisheries used a minimum 89% and 53% of the range over which our study tracked D. gibsoni and D. antipodensis respectively. Of 18 D. gibsoni and 35 D. antipodensis banded birds recovered dead since 1971, 22% and 83% respectively were related to fisheries. The areas where closures of fisheries would be most likely to reduce bycatch are identified.
Photo essay compiled by Murray Williams from text an photographs provided by Don Merton, with additional photographs from Department of Conservation, Hocken Library and Archives New Zealand.
Breeding of North Island kokako (Callaeas cinerea wilsoni) was studied at Mapara, King Country, New Zealand, from 1990 until 2000. Sixty-seven adult and 167 nestling kokako were colour-banded, and radio-transmitters were attached to 49 to identify individuals and to help locate nests. Pair bonds were stable: 7% of pairs split each year for reasons other than mate death. More than 200 nests were located, which permitted observations of breeding-season length, nesting behaviour, clutch and brood size, incubation and nestling periods, and nest success. The nesting season began in late Oct but varied greatly in duration, lasting from 7 weeks in 1993/94 to 21 weeks in 1994/95. We attributed this variation to changes in abundance of key food fruits. Females made up to 5 breeding attempts and fledged as many as 6 chicks in a season. Male-male pairs also built nests, though the apportioning of effort differed from that of conventional pairs. Mean clutch and brood sizes were 2.31 and 1.96, respectively. The incubation period was 18 days and fledging took a further 34-42 days. Sixty-one percent of nesting attempts successfully fledged young when mammalian pests were controlled, as against 8% when there was no predator control. Predation of eggs and chicks by ship rats (Rattus rattus) and brush-tailed possums (Trichosurus vulpecula) was the main cause of nest failure, whereas deaths of nesting adult females mostly caused be stoats (Mustela erminea). Kokako are well adapted to cope with avian predation, but their future conservation depends on management of key small mammalian pests.
The little information that we have on the breeding ecology of the extinct Stewart Is snipe (Coenocorypha aucklandica iredalei) is based on books published by Herbert Guthrie-Smith and Major Robert Wilson following visits to Big South Cape I in 1923 and 1931 respectively. Wilson was a member of a party including Edgar Stead, who collected 4 clutches of eggs now in Canterbury Museum. We summarise the published information on breeding ecology of the Stewart Is snipe, and provide new information based on previously unpublished photographs of nests, and notes made by members of the 1923 and 1931 visits to Big South Cape I, including Edgar Stead’s unpublished diary. Stewart Is snipe appear to have had a different chick-rearing strategy from all other Coenocorypha snipe, with pairs jointly caring for a single chick. Guthrie-Smith’s 1923 record of courtship-feeding was the 1st reported instance for the entire family Scolopacidae.
The doubly-labelled water technique was used to measure energy expenditure in 20 free-living kakapo (Strigops habroptilus) on Codfish and Little Barrier Islands. Daily energy expenditure (DEE) averaged 799 kj/d, equivalent to 1.4 x BMR (basal metabolic rate), the lowest value recorded for any adult wild bird. DEE was higher in males than females, and was greater on Codfish Island than on Little Barrier Island. Supplementary food taken from hoppers by kakapo supplied about half of their DEE; a few individuals apparently obtained virtually all their energy needs from supplementary food. Use of food from hoppers did not affect energy expenditure directly, but apparently did so via long-term elevation of body mass. Supplementary feeding, particularly of energy-dense items such as nuts and seeds, greatly depressed body-water turnover rates. Some implications of the often high level of supplementary food taken by kakapo are discussed. Adjusting the supplementary feeding programme to meet more precisely the needs of individual birds would probably improve the overall nutrition of the surviving kakapo population.
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.