The kakapo (Strigops habroptilus) is a nocturnal, herbivorous parrot that shows lek behaviour and does not breed every year. When breeding does occur, egg-laying and incubation in mid-summer are followed by a prolonged period of chick-rearing, with all parental care provided by the female. Breeding years for kakapo are associated with mast seeding years for a range of forest trees and plants, and the periodicity of kakapo breeding is linked with the periodicity of years of large seed and fruit production by their major plant foods. Kakapo are likely to have an annual cycle of gonadal growth and regression driven by the annual cycle of day length, with breeding occurring in years when kakapo respond to cues from a range of plant species that undergo masting. Kakapo breeding is initiated in response to cues that appear in early summer, but in some years there is insufficient food for the rearing of young in the following autumn. Rimu (Dacrydium cupressinum) is an important food source for chick rearing and is likely to provide an important cue for kakapo in areas where rimu is present.
Between 1992 and 2002, the 4 main colonies of the king shag (Leucocarbo carunculatus) in the outer Marlborough Sounds, New Zealand were surveyed 10 times. Additional information was gathered at 2 smaller colonies off D’Urville Island. The average total population was estimated to be 645 birds, with 92% at Duffers Reef, Trio Islands, Sentinel Rock, and White Rocks, including 102-126 breeding pairs, with an annual recruitment of 40-68 birds. Surveys before 1992 may have included only c. 40% of the population, because most counts seem to have been done during the middle of the day when significant numbers of shags were absent feeding. If historic counts at colonies are adjusted for birds absent feeding, numbers appear to have been stable for at least the past 50 years — and possibly over 100 years — which would suggest a long-term balance between recruitment and mortality.
Vegetation in the Esperance Valley, Milford catchment, Fiordland, as it was in February and March 1974, is described using quantitative data for part of the valley that included home ranges of two male kakapo (Strigops habroptilus). One home range, of only 1.8 ha, was sited at 700 – 730 m altitude and extended over a gently-sloping river terrace covered in snow totara (Podocarpus nivalis) scrub with short silver beech (Nothofagus menziesii) forest at its margins. The other home range was 4 ha in area, sited on a very steep (42°) valley wall mantled with unconsolidated avalanche debris at 800-860 m altitude, faced NW and was covered by Blechnum capense fern – shrubland and short silver beech forest communities. At that time, this valley differed from most other parts of Fiordland: although possums (Trichosurus vulpecula), stoats (Mustela erminea) and rats (Rattus spp.) were present, ungulates were absent or very localised. Results gave no indication that food was limiting kakapo numbers in the Esperance Valley and we conclude that, because of the extreme vulnerability of females and their eggs, nestlings and fledglings to introduced mammalian predators, stoats were the most probable primary cause of kakapo decline in Fiordland.
Satellite telemetry can provide unique information on the biology and behaviour of mobile animals such as albatrosses. Determining areas of concentrated activity, essential resources and time-related changes in range use is of great importance for theoretical biology, practical conservation, and fisheries management. Utilisation Distributions (UDs), from a probabilistic model of the relative time spent by an animal in an area, were prepared using a kernel function in a Geographical Information System. Properties of the model were investigated, using satellite-tracking data from six northern royal albatrosses (Diomedea sanfordi) during eight over-wintering visits to seas off South America. We analysed UD areas and shape for different settings of the kernel smoothing parameter, a variety of location subsets associated with different sample sizes, sampling time periods and telemetry regimes. Small samples and intermittent transmission regimes reduced the UD range area. Individual bird data sets were combined to give comparable UDs. The UD model may help comparison of range areas and the identification of resource use, but they cannot identify an activity without additional information. For pelagic seabirds, UD preparation and interpretation require judgement and care.
We studied the distribution along the Pacific coast of South and Central America of three large petrels species that nest on New Zealand and subantarctic islands: white-chinned petrel (Procellaria aequinoctialis), Parkinson’s petrel (P. parkinsoni) and Westland petrel (P. westlandica). During 15 cruises from 1980 to 1995, we conducted 1,020 hrs of surveys over 14,277 km2 of ocean from the shoreline to 1500 km off the coast from Chile north to Panama, and recorded 2114, 179, and 20 individuals, respectively, of the three species. White-chinned petrels occurred throughout the study area, but were most abundant off Chile, Parkinson’s petrels were most abundant along the coasts of Ecuador and Peru, and Westland petrels off southern Chile. All three species preferred waters over the continental slope, although Parkinson’s petrel was abundant also over the continental shelf during the austral winter. Densities of each species were positively related to oceanographic properties that are associated with up-welling features. Abundance estimates, analyzed using generalized additive models, peaked during the non-breeding season of each species. Estimates were 722,000 White-chinned petrels during austral autumn (95% confidence interval “CI” = 349,000 – 907,000); 38,000 Parkinson’s petrels during austral autumn (95% CI = 28,000 – 50,000); and 3,500 Westland petrels during the austral spring (95% CI = 2,000 – 6,400). Scavenging appeared to be the primary feeding method of Procellaria, a habit that would make them susceptible to mortality as a result of their regular association with commercial fishing operations, particularly the recently developed long-line fishery on the continental slope of Chile.
A census of Chatham Island shag (Leucocarbo onslowi) and Pitt Island shag (Strictocarbo featherstoni), both endemic to the Chatham Islands, New Zealand, was conducted during their 2003/04 breeding season. Totals of 271 pairs of Chatham Island shags and 547 pairs of Pitt Island shags were recorded. Compared with the only previous survey (in 1997/98), numbers of both species were significantly lower. This decline most likely reflects broad scale marine changes affecting the birds’ food supply. Alternatively, it may suggest variability in the timing of breeding between seasons.
Corrections to figures and legends in McAllan, I.A.W.; Hobcroft, D. 2005. The further spread of introduced birds in Samoa. 52(1): 16-20
Foraging of female rockhopper penguins (Eudyptes chrysocome filholi) during the chick stage was investigated at Antipodes Islands during December 2002 – January 2003. During the guard stage eight birds were tracked to foraging areas 22 – 54 km NNE or E from their nests. Birds foraging NNE did so over waters 500-1500 m deep, while those that travelled E foraged in water > 1500 m deep. The mean duration of these foraging trips was 1.37 days, significantly (p 1500 m deep. Male parents guarded the chicks more or less continuously, with most females returning to feed the chicks from mid afternoon. In the post-guard stage, most male parents returned to the nest each evening, but fewer females attended the nest at this time. Weight increases indicated that chicks were fed, on average, about once per day during both the guard and early post-guard stages. The foraging trips of female rockhopper penguins at Antipodes Islands were usually of longer duration and extended farther from the nest than birds breeding at Amsterdam, Kerguelen and Crozet Islands, but occupied a similar time and covered a greater distance than birds breeding at Staten Island. However, they were of considerably shorter duration and distance than birds breeding at Macquarie Island. This may be related to the differing marine environments around each of these breeding locations.
A trial translocation to establish a new fluttering shearwater (Puffinus gavia) colony is reported. From 1991 to 1996, 334 fluttering shearwater chicks were transferred from Long Island to Maud Island, Marlborough Sounds, New Zealand. Chicks were artificially housed and hand-fed until fledging. Overall fledging success was 82%, 32 of the 273 chicks that fledged returned to Maud Island, and 30 have bred. Mean age of fi rst breeding was 6.8 years (range 5-10 years). Returning chicks were heavier at fledging and spent longer on Maud Island than chicks that did not return. Transferred chicks showed typical post-fledging behaviour by dispersing to southeast Australian waters. The new colony has gradually increased, and 15 pairs bred in 2003/04. Methods developed have application to endangered species management.
The Antipodean wandering albatross (Diomedea antipodensis) is endemic to Antipodes Island in the New Zealand subantarctic. A programme of regular census and population study was initiated on Antipodes Island in 1994 to determine the status of the species. This paper reports on field work carried out every summer from 1994 to 2005. Aspects of breeding biology are described and compared with those of other species of wandering albatross, particularly the closely related Gibson’s wandering albatross (D. gibsoni) on Adams Island. Average annual survival over 10 years was 0.957. Productivity was measured over 11 years and averaged 0.74 chicks per nesting pair. Survivorship was similar to that in the increasing Diomedea exulans population on Crozet Island, and productivity higher than recorded in all other wandering albatross populations. Between 1994 and 1997, the average annual number of pairs nesting on Antipodes Island was 5136. There is evidence of population decline during the 1970s but numbers are now increasing.
Observations of birds on Antipodes Islands during 24 April – 6 June 2001 represent a season of the year for which data are lacking. Activity ashore of non-breeders of summer-breeding gadfly petrels Pterodroma spp. and black- bellied storm petrels (Fregetta tropica) continued until late May or even June. Data were obtained on the non-breeding behaviour, breeding cycle and burrow occupancy rates of grey petrels (Procellaria cinerea); only 50% of their burrows were occupied by breeding pairs. White-capped albatross (Thalassarche steadi) fledglings on Bollons Island were counted. There had been an autumnal immigration of some Passerines. Birds seen at sea on the voyages from Akaroa, Banks Peninsula and returning to Port Chalmers, Dunedin included the rarely-sighted Chatham taiko (Pterodroma magentae).
We examine whether mist-netting and handling of birds (including taking blood samples) during the pre-nesting period caused egg-laying to be delayed in a threatened species, South Island saddleback (tïeke) Philesturnus carunculatus carunculatus. We used data on egg-laying dates of first clutches for 12 pairs in 2002-03 and 22 pairs in 2003- 04, of which 3 (2002-03) and 7 (2003-04) pairs had been caught and handled. There was a significant delay in the peak laying period of first clutches in 2003-04, which was associated with more birds being caught and handled. However, pairs that were handled showed typical laying dates of first clutches for both experienced and inexperienced pairs, and there was no significant correlation between the date when a pair was caught and the date of laying its first clutch. There were also no significant differences between handled and non-handled pairs in the number of chicks raised or fledged. Like saddlebacks, Stewart Island robins Petroica australis rakiura monitored at the same site showed a two-week delay in the average laying dates of first clutches in 2003-04. The five inexperienced robin pairs in 2002-03 laid their first clutches earlier in 2003-04, but all three experienced pairs laid later. Weather data indicated it was substantially colder before the nesting period in 2003 compared to 2002, suggesting that colder weather conditions plus a greater number of inexperienced pairs caused a delay in peak egg laying in both species in 2003-04 relative to 2002-03. We conclude that mist-netting, banding and bleeding – standard technique used in present-day research of threatened avian species – did not have any measured short-term effects on nesting behaviour or breeding success of South Island saddlebacks.