I visited 10 breeding sites across the range of Fiordland crested penguins (Eudyptes pachyrhynchus) in 1995. Based on the developmental stage of chicks at each of the sites, breeding begins progressively later in more northern colonies. Fiordland crested penguins had unusually high hatching success on Taumaka I. (Open Bay Islands) in 1995, and I suggest from anecdotal observations made at the nine other sites that 12% of pairs may have raised two chicks in that year. Together, these observations suggest that Fiordland crested penguins had an unusually good breeding season in 1995. The suggestion that rare “good” years occur, allowing two chicks to be raised, has implications for explanations of brood reduction in crested penguins.
Breeding of North Island robins was monitored at two sites in Pureora Forest Park, central North Island, during the 19961 97 and 1997/98 breeding seasons. A total of 146 nests was found. First clutches were laid in September-October (mean: 20 September) and last clutches in November-January (mean: 17 December). Pairs had time to rear three broods during the breeding season (September-March), although most reared only two. Nest materials and nest location are described: mean nest height was 5.3 m (range 1.0 – 13.6). Mean clutch size was 2.60 (clutches of 2 or 3). Monthly mean clutch size increased from September to November, then decreased. The breeding biology of the North Island subspecies of robin at Pureora was similar to that of the South Island robin at Kaikoura. Nesting success improved dramatically after brushtail possums were poisoned by aerially distributed 1080 (sodium monofluoroacetate) baits, because mammalian predators were also poisoned. Robins are easy to monitor, and predation is a common cause of nest failure, so the species is potentially a valuable indicator of predator activity.
The nesting activities and breeding success of black shags (Phalacrocorax carbo) near Lake Kohangatera, Wellington, were studied from 1993 to 1998. The colony was used during November-July by a mean of 67 birds per night, but in August-October numbers increased to a mean of 98 birds when fledglings were present. Courtship and nest-building began in March, and nesting continued until October-November when the last chicks fledged. Most clutches (85% of 185) were laid in April-May (early nests), the remainder being laid in June-September (late nests). The mean estimated laying date of early nests varied from 14 April in 1998 to 3 May in 1995, the overall mean (1993-98) being 24 April. During the day typically the male took two incubation stints, including the first, and the female one or two. The mean length of incubation stints by females was 3 h 46 min, over an hour longer than that of males. However, the mean time females and males were absent from the colony to forage, 2 h 39 mins and 2 h 21 mins respectively, did not differ significantly. Three types of changeovers seen during incubation are described, as are the activities of adults and chicks during nestling rearing. Fledglings took their first flights when 49-60 days old, but continued to be fed by their parents for 40 to 80 days afterwards, the oldest fledged young seen fed being about 140 days old. Of 185 breeding attempts during 1993-98, 83% were successful, the majority resulting in one or two fledglings per nest. Mean brood size at fledging varied with year, from 1.1 in 1997 to 1.7 in 1998. Overall, the mean brood size was 1.4 fledged young per nest, and 1.7 for successful attempts. Early clutches were more productive than late ones. We conclude that a pair of black shags would be unable to successfully rear two broods and complete their moult within a year, and that late nestings were replacement clutches.
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.