The timing and breeding success of starlings (Sturnus vulgaris) in nest boxes was monitored simultaneously at 5 localities representing northern, central, and southern New Zealand. The northern locality, (Kaikohe, 35° 25’S) was monitored for 2 consecutive years; the others, of which Winton (46° 10’S) was the southernmost, for 4 consecutive years. The median date for the laying of Oct clutches was always earlier at Winton except in 1978 when it was 4 Oct at both Kaikohe and Winton. In any 1 year the size of Oct clutches (4.43 pooled over all years and localities) and the number of young in successful broods was always greater at Winton than elsewhere. In both 1977 and 1978 the difference in laying dates between Ohau and Waikanae (only 27 km apart) was greater than between Kaikohe and Winton at opposite ends of the country. The 5 localities showed no consistent trend, one with another, in their respective median laying dates from 1 year to another. The mortality of chicks was highest at Kaikohe, except for Belmont in 1978 when the 65% mortality was attributed to stoats (Mustela erminea). The laying of 2nd clutches has a very weak genetic basis and is probably a response to environmental factors.
The Campbell Is snipe (Coenocorypha undescribed sp.) was unknown to science until its discovery on 19 ha Jacquemart I in 1997. Following the successful eradication of Norway rats (Rattus norvegicus) from 11,268 ha Campbell I in 2001, there was increasing evidence that snipe had begun to recolonise the main island: footprints were found at Monument Harbour in 2003, and a fully-feathered dependent chick was captured nearby in Mar 2005. A survey of Campbell Is snipe recolonising Campbell I was undertaken by the authors and a trained bird-locater dog during 7-15 Jan 2006. We confirmed the presence of snipe and their successful breeding at 2 sites: the outlet to Six Foot Lake (head of Monument Harbour), and near the mouth of Kirk Stream at the head of Six Foot Lake. We estimated at least 22 adult snipe to be present. Twelve adult snipe were caught, along with 5 dependent chicks with estimated ages ranging from 8 to 37 d. One snipe nest was found. Subsequent sightings in Feb 2006 revealed at least 2 snipe to be present on the north-western shores of Perseverance Harbour, c. 3 km north of where we recorded them. We document the successful re-establishment of snipe on Campbell I within 5 years of rat eradication, and recommend that their natural recolonisation be left to continue unaided.
Seasonal changes in home range size and habitat selection of kakapo (Strigops habroptilus) were investigated on Maud Island. Kakapo were radio-tracked at night in each of the four seasons between December 2000 and October 2001. Home ranges were estimated for four adult males, three juvenile males and two juvenile females in each season and for nine females in summer, each based on 20 radio-fixes per season. Home range size varied from 1.8 to 145.0 ha using the minimum convex polygon method. Home ranges were smallest in winter. Habitat selection was determined by overlaying the kakapo locations and home ranges on a vegetation map of the island. For each season selection ratios were calculated for each vegetation community. Pine plantation (Pinus radiata) was selected for in summer, whereas the treeland community dominated by five-finger (Pseudopanax arboreus) was selected for in the autumn. Dense pole stands of manuka (Leptospemum scoparium) and pasture communities were avoided by kakapo.
We studied the New Zealand morepork (Ninox novaeseelandiae) over 2 breeding seasons on Mokoia I, Lake Rotorua, North Island, New Zealand. Ten pairs were monitored in the 1995/96 breeding season and 8 in the 1996/97 season. Nest sites included tree cavities, hollows amongst tree fern fronds, nest boxes provided for saddleback (Philesturnus carunculatus) and scrapes on the ground. Nest cavities were 0-5.2 m agl. Clutch size was 1-3 eggs; egg dimensions averaged 39.0 mm × 32.9 mm. The incubation period for 1 clutch was at least 24 days. Only females were observed to incubate eggs and brood nestlings; males roosted nearby. Two chicks were weighed and measured throughout their development and the nestling period was determined for 1 chick. Nestling development is described. Breeding success was lower in the year after a poisoning operation to eradicate mice from the island. Juvenile mortality was high after fledging. The dispersal of 3 juveniles was monitored, and females appeared to move earlier and disperse farther than males.
The context of modern conservation management of kakapo is introduced and a brief overview of the research presented in this special issue of Notornis is provided.
182 bird taxa have been recorded from the Chatham Is archipelago, including 32 reported here that are additional to the most recently published reviews in 1990 and 1994. Nine of these new records are from subfossil bone deposits; the remaining 23 are new records of vagrants or colonists, although 2 result from taxonomic revision of albatross species, where it is not clear how many terminal taxa had been recorded before 1994. Antipodean albatross (Diomedea antipodensis), Salvin’s mollymawk (Thalassarche salvini), and Indian yellow-nosed mollymawk (T. carteri) were recorded breeding on the Chatham Is for the 1st time since 1994, with the latter being the 1st breeding record for the New Zealand region. Notable among the list of over 100 vagrant species recorded from the Chatham Is are the only New Zealand records to date of Atlantic yellow-nosed mollymawk (T. chlororhynchos), and willie wagtail (Rhipidura leucophrys).
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.
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.