The distribution, speciation and probable evolution of New Zealand parakeets are outlined. Specific ecological adaptations keep closely related sympatric species separate. Examples are given of such ecological isolating mechanisms in Antipodes and Chatham Island parakeets. Occasionally, where man has drastically modified the environment, these barriers break down and widespread hybridisation occurs, as on Mangere Island, Chatham Islands. The existence of the very rare Chatham Island yellow-crowned parakeet (Cyanoramphus auriceps forbesi) is endangered by habitat changes and hybridisation.
Observations and data are presented from an expedition to Korapuki Island between 25 November and 2 December, 1974. The vegetation composition and communities are mapped and a checklist of plant species identified and compiled from this and former expeditions is presented. Seven species of seabird are now recorded as breeding on Korapuki Island and their respective burrow distribution and density is outlined. A breeding record of the sooty shearwater is the first for the species breeding on this island. The grey-faced petrel is the most abundant breeding seabird on the island with an estimated 600–700 pairs. Fifteen species of bush bird are noted, of which the shining cuckoo, long-tailed cuckoo and morepork are new records. Four of the five lizard species previously collected from this island were found, the exception being Sphenomorphus pseudornatus. It is considered that the habitat of Korapuki Island is marginal for this species. Stomach examination of rats trapped on the island reveal a high frequency of occurrence (49%) of bird remains. The rabbit population is considered low compared with data collected from previous expeditions. The soil and litter fauna showed a lower diversity and abundance than that found on the adjacent Coromandel mainland. Large invertebrates were noticeably rare, due possibly to predation by rats. An incidental insect list is also presented.
Ten samples of South Island pied oystercatchers (Haematopus ostralegus finschi) were trapped between August 1969 and June 1971. Nine catches were made at the Heathcote-Avon estuary and one at Parapara Inlet in northwest Nelson. In late summer large numbers of immatures and adults arrived at the estuary. Decreasing frequencies of juveniles in later samples suggest that young birds tend to move further north than most adults. Males outnumbered females in all samples except the one in February 1971 when there was an excess of females. This seasonal shift in sex ratio could arise from a staggered migration and/or differential mortality of the sexes. Further systematic trapping at strategically placed coastal haunts is needed to substantiate and elaborate the above findings.
Two pairs of moreporks (Ninox novaeseelandiae) in dense rata-podocarp and open beech forest were radio-tracked between August and October 1973. The home range of both pairs (minimum size 3.5 and 5.3 ha, respectively) included each forest type, and both pairs used several roost trees. During seven years of regular mist-netting 20 different owls passed through the two territories. Some of them, possibly juveniles, were caught only once and others up to 15 times. In each territory one bird was present for more than five years.
The adoption of Whero Island as a breeding station by the dimorphic Stewart Island shag over the last 20 years is described. A review of other known breeding stations of this subspecies suggests that breeding sites are subject to periods of nontenancy. The relatively few records of the Stewart Island shag indicate a distribution restricted to Foveaux Strait, and the Otago coast at Moeraki and near Dunedin. The total population is unlikely to exceed a few thousand birds.
This series attempts to condense observations made over seventeen years in areas being milled west of Taupo from 1944 to 1946 and in the south-west Urewera from 1946 to 1961. Daily counts were made of all birds seen and compiled into monthly charts. Estimates were made of birds heard only and notes kept of locality, weather and temperature, with sundry notes on song, calls, foods, breeding and behaviour. The files of charts are to be deposited in the library of the Ornithological Society of New Zealand Inc., Auckland Institute & Museum. For each species there is given an account of general observations and, where significant, a breakdown of figures from the monthly charts. Part A deals with bellbird and tui.