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 first 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.
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 (tīeke) 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.
Five introduced bird species were observed in the wild in Samoa in November 2004. The red junglefowl Gallus gallus maintains wild populations in the mountainous areas; the rock dove Columba livia is presently confined to urban areas; and the red-vented bulbul Pycnonotus cafer and jungle myna Acridotheres fuscus have increased their ranges markedly over the past six years. The last two species, found in most inhabited areas, may be close to their maximum possible distribution in Samoa. The common myna Acridotheres tristis has also increased in range significantly and efforts should be made to control this species.
Bird species introduced to New Zealand from high northern latitudes are expected to change their breeding behaviour to conform to well-known geographic gradients in avian reproductive parameters. Here, we demonstrate reductions in average egg size and clutch volume for eight species of exotic passerine originating in the UK, and show that the magnitudes of these reductions appear to trade-off against reductions in annual variation in clutch size. Possible reasons for the trade-off are discussed.