Historical records of the Chatham Island oystercatcher (Haematopus chathamensis) suggested a sparse and small population. In 1970, there may have been as few as 52 birds, but this apparently increased to 112 in 1987 and 144 in 1998. Intensive predator control and nest and habitat management has since boosted productivity and recruitment of oystercatchers along the northern Chatham Island (Rekohu) coastline and resulted in a rapid increase in total numbers; by 2004 there were 316–340 birds, including 89 pairs. In 2005–2006 management effort was shifted to Pitt Island (Rangiauria) in the southern range of the species. Although low productivity contributed to the total population levelling off at about 313–351 birds in 2006, ongoing recruitment of young birds resulted in an increase to 109 pairs. Currently, there are fewer than 250 mature individuals and therefore the species remains a high priority for conservation management.
Roost sites in Whangarei Harbour and Ruakaka Estuary were used regularly by 12 wader species and 6 other species were present occasionally between 1974 and 2000. Counts at 7 roost sites in Nov, Jun/Jul, and Mar showed that 4 species, eastern bar-tailed godwit (Limosa lapponica), lesser knot (Calidris canutus), pied stilt (Himantopus leucocephalus), and South Island pied oystercatcher (Haematopus ostralegus finschi) contributed 70-99% (median 94%) of the waders. Most of the common waders used several roosts at each tide, but numbers and species richness of resident and vagrant species were greatest along the southern margin of the harbour. Changes in roost structure and proximity to feeding areas, and differences in migration patterns affected counts at individual roosts and the overall totals of wading birds counted in the harbour and its environs.
We report the 1st use of a satellite transmitter to track the endemic New Zealand falcon (Falco novaeseelandiae). The movements of an adult female bush falcon in Kaingaroa Forest east of Lake Taupo, central North Island were monitored during a 3-year period from Feb 2002. The geolocations of the falcon were mapped and revealed that the falcon remained close to her nesting territory throughout the study. The home range included an area of c. 200 km2. The falcon nested in pine compartments (0–3 years old) for 3 consecutive years; her nests averaged 5 km apart. After nightfall the falcon was located within the 95% isopleth of her home range, highlighting her sedentary nature. During the breeding season the falcon appeared to wander outside of her home range, with the furthest recorded distance from its centre being 137 km. Throughout the 3 years, observations suggest the falcon preferred to stay close to open areas, which may be related to the frequency of hunting opportunities.
Following the translocation of North Is kokako (Callaeas cinera wilsoni) to Kapiti I, southern North Is, New Zealand, Department of Conservation staff noted that most pairs were forming between individuals that came from the same source origin. This study investigated whether geographic variation in dialects influenced mate selection and, ultimately, pair formation on Kapiti I. Between Nov 1999 and Mar 2001 songs of male kokako that had paired and were resident at a single site were recorded. In addition, recordings were obtained from the Department of Conservation of birds in the source areas. Analysis of the songs indicated that kokako songs were typical of their areas of origin at the time of translocation and differed from songs of birds from different source areas. Translocated female kokako preferentially chose males whose repertoire was typical of the acoustic environment they experienced before translocation. Song analysis and pair formation of kokako born on Kapiti I indicates that the observed assortative mating was a temporary phenomenon in the years after translocation, which did not continue following juvenile recruitment.
New Zealand average atmospheric temperature showed little increase from the 1850s onwards for almost 100 years, but increased rapidly after c.1940. The increase in temperatures was accompanied, at least in parts of New Zealand, by an increase in precipitation,. We investigated the relationship between the arrival years (1st breeding) of the bird species that self-introduced to New Zealand during the 20th century and the period of turpentine increase. Because these birds come from Australia the warming might be a prerequisite to colonize New Zealand. When considering the 1st breeding years as events in a univariate point process the process is non-stationary and the rate function has its estimated maximum in 1953. This estimate may indicate that the sequence of invasions of New Zealand by additional bind species could be a response to climate changes although the coincidence is on its own not sufficient to prove that climate changes have affected the self-introduction of birds from Australia into New Zealand. Alternative and additional explanations are discussed.
The grey warbler (Gerygone igata) is the main host of the shining cuckoo (Chrysoccocyx lucidus) in New Zealand. I describe 4 observations of egg-laying by shining cuckoos in the nests of grey warblers, and 2 observations of adult cuckoos evicting, or attempting to evict, nestling warblers from non-parasitised nests. Nest were parasitised from 0658 to 1731 h NZDT, and the cuckoos took 5–18 s to lay their egg. In 3 nests in which it could be determined, the cuckoo left the nest with an egg in its bill. Warblers were present at 2 nests during parasitism and responded by attacking the cuckoo. Cuckoos evicted nestlings by pulling them out through the nest entrance and throwing them on the ground. Head- wounds on evicted chicks suggest they were pecked. Nestling eviction by adult shining cuckoos has not been previously reported and it may be a strategy to increase nest availability by inducing hosts to relay.