During 1965, 1406 sea birds and during 1966, 1102 sea birds were recovered from 1064 km and 785 km of New Zealand beaches. Monthly recovery rates indicated that sea bird mortality was usually higher in spring and summer (September to February) than in autumn and winter (March to August). Two wrecks were recorded during the two-year period, both on Wellington west coast beaches, and following periods of westerly or south-westerly winds. From September to December 1965 species affected included fairy prion, sooty shearwater, short-tailed shearwater, fluttering shearwater and diving petrel. In July 1966 there was a wreck of lesser broadbilled prions. Uncommon species found were blue petrel, Fiordland crested penguin, Pycroft’s petrel and Antarctic fulmar (all in 1965), and Arctic skua (in 1966).
Petrels, especially Procellariidae and Hydrobatidae, visit their breeding places in lesser numbers on moonlit nights than on darker nights. This is probably caused by poor feeding conditions because prey do not come so near the surface on moonlit nights. Fledgling petrels, mainly Procellariidae, are particularly liable to be attracted to artificial lights situated near the breeding colony. It is suggested that nocturnal-feeding petrels are instinctively attracted to light sources because they exploit bioluminescent prey. A small proportion of fledglings seem to be initially misled by this instinct.
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.