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From 13 to 18 December 1998, we counted Chatham Island Oystercatchers (Haematopus chathamensis) on approximately 310 km (96 – 97%) of the coastlines of Chatham, Pitt, Rangatira, and Mangere Islands, and 100 km (100%) of the shore of Te Whanga Lagoon, Chatham Island. A total of 142 adult Chatham Island Oystercatchers, including 34 confirmed breeding pairs and seven additional possible breeding pairs, was found. This is an increase of 20 to 40 adults over any previous count or estimate. Some of this increase may be due to efforts by the Department of Conservation to increase productivity of breeding pairs since the early 1990s along the northern coast of Chatham Island. Approximately 70% percent of the breeding pairs were on Chatham Island, 15% on Pitt Island, 10% on Rangatira and 5% on Mangere Island. Most of the oystercatchers (79% of individuals and 74% of the breeding pairs) were in areas we broadly defined as containing rocky wave-cut platform or other rocky coastline or outcrops. Thirty individuals and nine breeding pairs were on sandy beaches. One immature bird was on the shore of Te Whanga Lagoon.

Between 1979 and 1998, 6975 Arctic waders of seven species (mainly Lesser Knots Calidris canutus and Bar-tailed Godwits Limosa lapponica) were caught by the Miranda Banders and the New Zealand Wader Study Group near Auckland. Of these, 1375 were marked with a white leg-flag on the tibia to denote capture in New Zealand. Thirty-two Lesser Knots and three Bar-tailed Godwits had already been banded overseas, mainly in Australia. Another two Lesser Knots and two Bar-tailed Godwits banded overseas have been found dead in New Zealand. Up to 135 Lesser Knots, 34 Bar-tailed Godwits, 2 Turnstones and 2 Red-necked Stints (Calidris ruficollis) bearing Australian leg-flags, and 2 colour-banded Bar-tailed Godwits from Alaska have been seen in New Zealand. Of those birds banded or leg-flagged in New Zealand, up to 21 Lesser Knots, up to 17 Bar-tailed Godwits, and two Turnstones (Arenaria interpres) have been recovered or seen in six overseas countries. One Turnstone banded in New Zealand was caught in Australia and then recaptured back at its original banding site. The migration routes taken by Lesser Knots, Bar-tailed Godwits and turnstones visiting New Zealand have been deduced from these band recovery data.

Lesser Knots (Calidris canutus) are high-Arctic breeding waders that migrate to temperate and tropical regions for the non-breeding season. Seasonal mass changes were examined in Lesser Knots in New Zealand at the southern end of their migration. Adults showed a large increase in mass in February before their northward migration in March. They were estimated to depart with a ‘fat’ load of around 45%. Subadult birds, most of which winter in New Zealand over the northern breeding season, also showed a mass increase. Mass increases in winter are well documented for European waders but contrary to the European situation, this increase in subadult birds in New Zealand is unlikely to be an adaptive strategy to insure against periods of negative energy balance. Instead, it may be an endogenously orchestrated byproduct that has not been selected against in the pre-migratory period. Such increases may be more widespread in Arctic waders in the Southern Hemisphere than is realised.

Sections of nine rivers in the Upper Waitaki Basin were surveyed between 1991 and 1994 and these surveys were compared with counts completed in 1962, 1965 and 1968. A systematic account of 27 wetland birds is given. Densities (number of birds km-1) of birds were compared between the two periods. Species that increased in density were mainly common generalists, whereas species that decreased in density were endemic river breeding specialists. Densities of Wrybills (Anarhynchus frontalis), Spur-wing Plovers (Vanellus miles), Canada Geese (Branta canadensis), and Grey Teal (Anas gracilis) were higher in the 1990s than in the 1960s, whereas densities of Banded Dotterels (Charadrius bicinctus), waterfowl and shags, Black-billed Gulls (Larus bulleri), South Island Pied Oystercatchers (Haematopus ostralegus), Black-backed Gulls (L. dominicanus) and Black-fronted Terns (Sterna albostriata) were lower in at least one river in the 1990s compared to the 1960s. Estimated minimum populations of river birds published for the Ahuriri River (surveyed in 1982) and the Cass River (surveyed in 1979 and 1982) were usually intermediate to those recorded in equivalent 1960s and 1990s surveys. Four mechanisms that explain changes in braided river bird populations are suggested.

Between March 1992 and February 1993, 222 five-minute stationary bird counts were conducted at 12 sites in the Kennedy’s Bush Scenic Reserve on Christchurch’s Port Hills. Over the period of the survey, 22 species of bird were recorded in or flying over the reserve. The seven most frequently recorded species were Silvereye (Zosterops lateralis), Grey Warbler (Gerygone igata), Bellbird (Anthornis m. melanura), Fantail (Rhipidura fuliginosa), Chaffinch (Fringilla coelebs), Blackbird (Turdus merula) and Redpoll (Acanthis flammea). Kennedy’s Bush does not contain a high diversity of native bush birds compared to some other mainland sites. Native species also appear less abundant in Kennedy’s Bush than in continuous, climax forest sites near Reefton. Kennedy’s Bush does, however, support high numbers of some species such as Silvereye, Grey Warbler, Fantail, Bellbird and Shining Cuckoo (Chrysococcyx l. lucidus) compared to sites at Kowhai Bush, Kaikoura. The autumn peak in numbers of Silvereye recorded at Kennedy’s Bush may result from flocks of migrating birds, some of which may move out of the reserve for the winter months. The numbers of Grey Warbler, Bellbird and Blackbird recorded probably reflect seasonal changes in conspicuousness rather than a change in actual numbers; adults are probably resident in the reserve year round. As in other parts of Canterbury, Fantail numbers were severely reduced by the heavy snow-falls of August 1992. Bellbird numbers were also reduced by the heavy snow-falls. Spring brought high numbers of Chaffinches to the reserve and summer brought high numbers of Redpolls, both of which were apparently absent or in very low numbers during winter. Small numbers of Goldfinches (Carduelis carduelis) and Greenfinches (Carduelis chloris) also appear to occur in Kennedy’s Bush only during the summer months. Of particular interest were records of two rarer Port Hills birds, Tomtits (Petroica m. macrocephala) and New Zealand Pigeons (Hemiphaga n. novaeseelandiae). Tomtits were recorded on only two occasions over the survey period. By 1997, however, this species appeared to be resident in the reserve. New Zealand Pigeons were recorded in Kennedy’s Bush in small numbers throughout the year and may breed there.

Dispersal of colour-banded South Island Pied Oystercatchers Haematopus ostralegus finschi from a breeding area on farmland in mid-Canterbury, New Zealand, was investigated from December 1987 to September 1997. Most moved north and were away from the breeding area from late December to mid-July. All birds spent this time at coastal sites, which ranged from 97 to 834 km from their breeding area. Distances travelled by males and females and birds of all ages were similar. Birds had high fidelity to wintering sites within and between years. Pair bonds were not maintained in winter and there was no evidence that fledglings accompanied their parents to wintering sites.