A 15,000 ha low-intensity stoat (Mustela erminea) trapping network was established in the Murchison Mountains in 2002, primarily to protect the last natural population of the critically endangered takahe (Porphyrio hochstetteri). We compared the productivity and survival of threatened southern brown kiwi or tokoeka (Apteryx australis) living in 3 valleys that were covered by this trapping network with those in a nearby valley that was left untreated. Chick survival to 6 months old was significantly higher in the trapped areas (37%) than in the untrapped area (19%). This doubling of chick survival was sufficient to change the rate of population growth, as derived from Leslie matrix analyses, from a projected decline of 1.6% per annum without management to a projected increase of 1.2% per annum with trapping.
I recorded the calling behaviours of shining cuckoos (Chrysococcyx lucidus) from 1992 – 2015 on Kawau Island. The 3 most common calls, the upward crescendo “whistling call,” the downward slur “call-note,” and the “call-note” with “chatter” notes, were given from the arrival of adults in late August-early September until early January. After January only the call-note was heard. The upward whistling calls averaged 9.5 notes per calling bout (se = 0.18, n = 721). There was no significant difference in the number of whistling notes given with or without following notes. Single call-notes from lone cuckoos or groups of birds were restricted to specific sites on ridges. Calling was infrequently heard during evening twilight, and not heard during darkness. There was an increase in the number of cuckoo detections after 2009, and this corresponded with the appearance of communal behaviour and calling.
The valley of the South Branch of the Hurunui River, prior to 2001, held a dense population of the orange-fronted parakeet (Cyanoramphus malherbi). However, a rat plague in 2001 reduced this population by ~85%. In preparation for a restoration program of this species in the Hurunui valley, I analysed the distribution of sightings of orange-fronted parakeets, as well as the congeneric, yellow-crowned parakeet (C. auriceps) prior to the population collapse. My objective was to identify the areas and types of habitats used by each species. A vegetation survey showed significant differences between different parts of the valley floor study site, and this appeared to be reflected in the distribution of orange-fronted parakeets. Both species had significantly different distributions, and orange-fronted parakeets were recorded most frequently within forests growing on the river fan, an area characterised by mature red beech (Nothofagus fusca) and areas of dense regenerating mountain beech (N. solandri var. cliffortioides). While the valley has been subject to anthropogenic modification since the 1850’s, it still contains a relatively intact beech forest. My observations on the historic distribution of orange-fronted parakeets suggest this valley is still capable of supporting a large population of the species. However, the success of any re-introduction program is likely to depend upon continued preventative and reactive predator control, as well as a release programme that introduces enough individuals to prevent severe bottlenecks.
The breeding behaviour and development of New Zealand falcons (Falco novaeseelandiae) were recorded at 2 nests in Kaingaroa Forest during a 4-month period up to 2 March 2007. This covered the later part of incubation, and the entire nestling and early post-fledging periods. Incubation was shared between parents; the male primarily incubated the eggs, during which time the female hunted. The male only provided occasional prey for the female. Brooding by both parents was intensive for the first 6 days and then gradually declined until the chicks reached 14 days old at which point it ceased. Assisted feeding of the chicks was almost always undertaken by the female. The male’s primary role during the nestling period was prey delivery. During the early nestling period the female spent the majority of the time brooding chicks before shifting to hunting for the young.
We collated and reviewed 4179 records of the historic and contemporary distribution of the endangered specialist wetland bird, the Australasian bittern (matuku, Botaurus poiciloptilus), in New Zealand, to assess its current status and trends in its distribution across major habitat types. We mapped distribution in 5 time periods (pre-1900, 1900−1949, 1950−1969, 1970−1989, post-1990). We found that Australasian bittern are currently found throughout New Zealand with strongholds in Waikato, Northland and Auckland regions (46% of records) in the North Island, and Canterbury and West Coast (22%) in the South Island. They occur widely in freshwater and brackish riverine, estuarine, palustrine and lacustrine habitats. Australasian bittern were abundant (records of groups >100 birds) in Māori and early European times, but historical maps indicate their range appears to have been reduced by c. 50% over the last hundred years, with the most dramatic shrinkage in range occurring post-1970. Marked declines in occupancy began in Otago, Canterbury, Waikato, Wellington and Auckland regions between the 1900-1949 and 1950-1969 periods and reductions in range have been steady since. In comparison, declines in Northland, Southland, West Coast and Tasman/Nelson appear to be more recent and greatest between the 1970-1989 and post-1990 periods. The apparent shrinkage in range is supported by numerous observations in the literature. Australasian bittern distribution is now biased towards coastal areas and lowland wetlands of the North Island. Information indicates that range reductions were paralleled by marked declines in numbers: 34% of pre-1900 records were >1 bittern and 7.3% were >10, whereas post-1990, only 19% of records were >1 and 0.7% >10. The clearance and drainage of wetlands (c. 90% loss) and shooting were major causes of declines, but contemporary threats include continued habitat loss and degradation, accidental deaths from a range of causes, and predation by introduced mammals. Current trends in Australasian bittern populations suggest that they should be reclassified as Nationally Critical under the New Zealand threat classification system. Conservation management should focus on restoration of hydrology, water quality and aquatic food supplies, predator control, reedbed management and maintaining regional wetland networks.