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.
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 (Himantopus 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.
King shags (Leucocarbo carunculatus) dispersing to feeding areas from breeding colonies on the Trio Islands and Stewart Island began to leave colonies around dawn, and most had left by mid-morning. Foraging birds were distributed throughout Admiralty Bay, the average distance from the colony was c. 10 km, and were observed only rarely where the water depth was >50 m. Greater areas of mussel farms in inshore waters could potentially affect king shags by restricting the area available for foraging.
The breeding biology of kakapo (Strigops habroptilus) was investigated on offshore island refuges between 1990 and 2002. Male kakapo typically attended their display territories between October to April, with the primary courtship display, “booming”, usually beginning in January and ending in March. Mating was recorded from late December to March, with the median mating date falling in late January. Eggs were laid from early January to late March, with median dates of 24 January on Little Barrier Island and 7 February on Codfish and Pearl Islands. Females typically occupied a nest site eight days after their last mating (n = 44) and laid their first egg two days later (n = 40). Subsequent eggs were laid at three day intervals (n = 41). The mean and modal clutch sizes were 2.53 and 3 respectively, (range = 1 – 4, n = 54). Mean mass of fresh eggs was 40.53g (n = 122). Incubation began immediately after the first egg had been laid and the average incubation period was 30 days (n = 28). Mean nestling and fledgling periods were 72.4 (n = 27) and 246 days (n = 25) respectively. Male chicks began to grow more rapidly than females approximately one third through the nestling period. The mean fledging weights of 14 male and 14 female chicks were 1.93 and 1.72 kg respectively. Male kakapo are capable of mating at five years of age. Three known-age females first nested at 9, 10 and 11 years of age, respectively. Comparison with close relatives suggests that some aspects of kakapo breeding biology are evolutionarily conservative.
The anticoagulant brodifacoum is widely used for the control and eradication of vertebrate pests in New Zealand. During poisoning operations with this toxin, some native birds eat baits and die. Because brodifacoum persists in the environment, other birds may suffer secondary poisoning from eating animals that have ingested the poison baits.We describe here high mortality of New Zealand dotterels (Charadrius obscurus) following an aerial brodifacoum operation at Tawharanui Regional Park, North Auckland, in 2004. At least 50% of the dotterels in the area at the time of the operation disappeared or were found dead; one bird found freshly dead had a high liver level of brodifacoum residue. Sandhoppers (Talorchestia spp.) are a common food item of New Zealand dotterels. Sandhoppers at Tawharanui ate baits and accumulated brodifacoum and provided a potential route for transmission of the toxin to dotterels. Three pied stilts (Himantopus himantopus) and one spur-winged plover (Vanellus miles novaehollandiae) were also found dead. These records appear to be the first to document probable secondary poisoning of shorebirds in New Zealand. There was no apparent mortality of variable oystercatchers (Haematopus unicolor). Measures are suggested to reduce shorebird mortality in future operations of this type. Monitoring of New Zealand dotterels and other shorebirds during other types of poisoning operations in coastal areas is also recommended.
The “hakawai” is a rarely-heard but dramatic nocturnal aerial display performed by Coenocorypha snipe. Although much has been written about the hakawai formerly heard on islands off Stewart Island (performed by the extinct Stewart Is snipe C. aucklandica iredalei), there are few documented reports from other populations. We describe hakawai aerial displays heard on Adams I (Auckland Is snipe C. aucklandica aucklandica), Antipodes I (Antipodes Is snipe C. aucklandica meinertzhagenae), and Campbell I (Campbell Is snipe Coenocorypha undescribed sp.) between 2001 and 2006. These include the 1st records of hakawai on Adams I and Campbell I. Based on characteristic tail feather damage believed to be caused by the display, Campbell Is snipe of both sexes performed hakawai aerial displays more frequently than has been recorded for all other Coenocorypha snipe populations. Male snipe from all 6 populations assessed exhibited a higher frequency of tail feather wear than females, and for the 3 populations with adequate data, males also had lower wing-loadings, indicative of greater flying ability. However, there was no apparent correlation between the frequency of “hakawai” feather wear and wing-loadings when comparing between populations.