We review 16 published and 17 previously unpublished accounts of the nesting of North Island kokako (Callaeas cinerea wilsoni) recorded between 1880 – 1989. Nests were on average 8.5 m above ground, in many different tree species, but usually with dense overhead cover. Kokako laid eggs from October to February. The modal clutch had three eggs or young, four nests had two. Only the female built the nest, incubated, and brooded young, though the male fed the female at or near the nest throughout the nesting period. Incubation took about 18 days and fledging about 31 days. We suggest that several aspects of kokako nesting evolved in response to diurnal avian predation, and that these behaviours give ineffective protection against nocturnal, arboreal, introduced mammal predators.
During 1976-89, 490 black shag (Phalacrocorax carbo) nestlings were banded at Matthews and Boggy Pond wildlife reserves, and Te Hopai Lagoon, Wairarapa. Forty-one (8.4%) have been recovered, all dead, 20 of unknown causes. Of 21 for which the cause of death was known, 13 drowned in set nets, 11 of these birds being less than 6 months old. Six shags had been shot, all prior to 1986 when the black shag received partial protection. While 85% of the shags were found within a 100 km of the banding sites, mainly to the north and west, one bird was recovered about 2000 km away on Lord Howe Island.
The endemic New Zealand shore plover (Thinornis novaeseelandiae) is confined to a small population on Rangatira (South East Island) in the Chatham Islands. There are about 43 breeding pairs and 130 adults. The population is sedentary. Shore plover form monogamous breeding pairs in separate defended territories. Clutch size, parental behaviour, courtship, and defence displays are similar to those of other plovers. Shore plover have several unusual breeding characteristics which may be responses to the relatively constant environment and limited area of habitat on Rangatira, low prey abundance, differences in habitat quality, no mammalian predators, and the presence of certain avian predators. Shore plover are unique among plovers in nesting under cover, which protects their nests from avian predators and temperature extremes, but which would make nests very vulnerable to predation by mammals. Environmental conditions on Rangatira may also be a reason for the high hatching rate, low chick survival, and differing breeding success within the population.
Since the first burrows of Chatham Island taiko Pterodroma magentae were found in 1987/88, trapping around the burrows has killed 204 feral cats Felis cattus, 3053 possums Trichosurus vulpecula, 1572 weka Gallirallus australis and 589 rats Rattus spp. in 109,892 trap-nights to March 1993. No Taiko are known to have been killed by predators. Productivity was static at one fledgling per year until 1992/93, when two fledglings were reared. Unobtrusive studies of breeding biology indicated that mating occurred about 1 October, laying about 26 November, hatching about 20 January and fledglings departed about 4 May. The pre-laying exodus of females lasted up to 50 + days and chick-rearing took about 105 days.
The Incredible Kiwi
Kiwis. A Monograph of the family Apterygidae
Kiwi – A Secret Life
Handbook of Australian, New Zealand & Antarctic Birds. Vol I, Ratites to Ducks
Forest of several types covered 45.14% of South East Island, Chatham Islands (218 ha). All petrel burrows in 200 10 m2-quadrats in modified and unmodified forest were counted during breeding seasons in 1989 and 1990. From the total of 2675 burrows (1.338 burrows m-2 of forest), we estimated a breeding seabird population of more than 1.3 million pairs. The main species were white-faced storm petrels (Pelagodroma marina) (840,000 pairs), broad-billed prions (Pachyptila vittata) (330,000 pairs), and southern diving petrels (Pelecanoides urinatrix) (127,000 pairs). Smaller numbers of sooty shearwaters (Puffinus griseus), grey-backed storm petrels (Oceanites nereis) and Chatham petrels (Pterodroma axillaris) also bred in the forests. Comparisons are made with population estimates for other New Zealand islands, parts of the Galapagos Islands, Baccalieu Island (Newfoundland), and the Juan Fernandez group. Conservation issues for South East Island are discussed.
The carpometacarpus of the extinct, flightless gruiform Apterornis is described and illustrated, based on one specimen from the North Island form (A. otidiformis) and two specimens from the larger South Island form (A. defossor). The element is uniquely truncated distally, resulting in the loss of the distal portions of ossa metacarpalia majus and minus, the entire extremitas distalis carpometacarpi, and the spatium intermetacarpale. Although a few features of the extremitas proximalis carpometacarpi are variably discernable (e.g., trochlea carpalis, fovea carpalis cranialis, and fossa supratrochlearis), most features typical of the element in other Gruiformes are lacking. In both specimens for A. defossor, phalanx digiti alulae is synostotic with processus extensorius of the carpometacarpus, whereas in the single specimen for A. otidiformis the phalanx is absent. The absence of facies anicularis of phalanges digiti majoris and digiti minoris indicates the loss of both digits in Apterornis. The qualitative, flightlessness-related apomorphies of the carpometacarpus of Apterornis are unique among birds, and indicate a degree of alar reduction unequalled among carinate birds.
Fossil bones and earlier observations indicate that up to 22 species of bird have become extinct on Mangere Island. The extinctions appear to have been primarily a result of predation by cats, but human hunting and bush clearance are likely to account for the disappearance of some species. A crested penguin Eudyptes ?n.sp., two species of Pterodroma petrel, a shelduck Tadorna ?n.sp., Dieffenbach’s rail Gallirallus dieffenbachii, and a kaka Nestor ?n.sp. are present in fossil deposits on Mangere Island, but have not been reported from the island before. The relative proportion of remains in the deposits suggest that blue penguins Eudyptula minor, broad-billed prions Pachyptila vittata and sooty shearwaters Puffinus griseus have become more common on the island. Any such increases on Mangere Island, could have been a response of a few species to the large decrease in numbers and diversity that has affected seabirds as a whole at the Chathams. Some seabird species may have been able to increase because of reduced competition for food.