The Chatham Island pigeon or parea (Hemiphaga chathamensis) is an endangered species of pigeon endemic to the Chatham Islands. Effective conservation management of the Chatham Island pigeon required an understanding of its ecology and identification of the causes of decline. We studied the pigeon in their last remaining stronghold; the south-west of Chatham Island, New Zealand, between July 1991 and December 1994. We describe the nesting behaviour, nesting success, and the dispersal, survival, and recruitment of juveniles. The study was confounded by the lack of information on predator numbers or outcomes of pigeon nests from before the start of predator control activities within and adjacent to our study area. Despite a previously reported decline in pigeon numbers up until the early 1990s, during this study there was a 3-fold population increase, and only a low level of predation by possums and rats. Other than predation, no factor which might previously have limited the pigeon population was identified. We assume that the trapping and poisoning of pest-mammals since 1989, has been sufficient to allow the population of Chatham Island pigeon to recover.
Numbers of brown teal (Anas chlorotis) present at summer flock sites in Northland, New Zealand declined 65% during 1988-99 and the species’ principal range contracted to three enclaves located along 20 km of the eastern coast. Most populations underwent a period of gradual decline followed by an abrupt crash, symptomatic of prolonged recruitment failure. Drought-induced habitat and landscape change is proposed as an important agent of decline in two formerly large populations at Clendon Cove and Tutaematai. Extirpation in Northland appears imminent.
A captive-breeding programme was begun in August 1991 to breed North Island weka (Gallirallus australis greyi) for release at a North Island site. A total of 101 weka were released between October 1992 and January 1996 at Karangahake Gorge, southern Coromandel. The project was abandoned in March 1996 after dogs and ferrets (Mustela furo) killed many of the birds.
Rhys Philip Buckingham (MNZM) Member of the New Zealand Order of Merit, For Services to Ecology. David Edgar Crockett Companion of the Queen’s Service Order, For Public Services.
The South Island saddleback (Philesturnus carunculatus carunculatus) is one of two subspecies of the New Zealand saddleback. Despite the endangered status of this subspecies, it was not studied in detail until 1994, when 26 birds were released onto Motuara Island in the Marlborough Sounds of New Zealand. I report the foraging behaviour and diet of this reintroduced population during the first breeding season after release. South Island saddlebacks used their bills in a variety of ways when foraging, and were predominantly insectivorous. They obtained most food from the ground and five-finger (Pseudopanax arboreus), and the number of prey captured generally reflected the amount of time saddlebacks spent on foraging substrates. North and South Island saddlebacks are very similar in terms of foraging behaviour, prey handling techniques and types of invertebrate prey consumed. The foraging patterns and diet of South Island saddlebacks on Motuara Island differed from all potential competitors. I conclude that the success of the South Island saddleback transfer to Motuara Island should not be threatened by a lack of food or foraging opportunities.
During the 1997/98 breeding season we counted the breeding populations of Chatham Island shag (Leucocarbo onslowi), Pitt Island shag (Stictocarbo featherstoni) and black shag (Phalacrocorax carbo). Surveys, on foot or from kayaks and fishing boats, of all potential shag nesting habitat within the Chatham Islands provided the first complete census for shags breeding there. The breeding population of Chatham Island shag was 842 pairs in 10 discrete colonies, while there were 729 breeding pairs of Pitt Island shag at 63 locations throughout the group. Given that the counts of the endemic shags are for the total world populations. these species are extremely rare. The black shag breeding population was 233 pairs, in 5 locations on Chatham Island only. Comparisons with counts made during the 1960s and 1970s by visiting ornithologists suggest that the populations of Chatham Island shag and black shag have remained relatively stable, although the distribution of colonies of both species has changed significantly. Too few previous counts of Pin Island shag colonies were available to determine a population trend. All 3 species are threatened in the Chatham Islands by destruction of nesting habitat, disturbance of nesting colonies, human persecution, and predation by introduced mammals.