The breeding behaviour of Tanga’eo or Mangaia Kingfisher (Halcyon tutu ruficollaris) on the island of Mangaia in the Cook Islands was investigated in 1992. Calls and breeding behaviour are described from a study of pairs and trios. At least six calls were distinguished. Clutch size appeared to be two eggs for pairs and three eggs for trios. Incubation time was between 21 and 23 days, while the fledging period was estimated at approximately 26 days. Both birds of a pair and all members of a trio excavated nest holes, incubated, brooded and fed the chicks. In trios with two males, both males courtship fed and copulated with the female, suggesting a polyandrous relationship. The breeding behaviour and relationship of trios, and the effects of Mynas on breeding success warrant further investigation.
We present new distributional data from the eastern South Pacific Ocean for the White-headed Petrel (Pterodroma lessonii), Kerguelen Petrel (P. brevirostris), and birds showing characters of the endangered Magenta Petrel (P. magentae). Extrapolation of density for White-headed Petrels suggests a pelagic population of 18,770 birds for the 10( x 5( block of subtropical surface waters between 27-37(S and 80-85(W (August 1995). Two Kerguelen Petrels were noted off Chile at around 40(30’S 74(50’W (August 1995). Three sightings of apparent Magenta Petrels between 28(44’S 72(40’W (March 1992) and 36(24’S 78(02’W (August 1995) are reported to alert observers to the potential occurrence of this species off South America.
Five surveys for the North Island Kokako were carried out in the Hunua Range, Auckland between October 1992 and March 1994. Twenty six-28 Kokako were recorded, including 3 possibly 4 pairs. Results suggest that there has been a decline in Kokako numbers since the previous survey in 1986-1988. All Kokako were recorded in tawa-podocarp forest. The birds ranged in altitude between 320m and 640m. Birds were distributed in the following catchments: Mangatangi (13 birds), Mangatawhiri (12 birds), Orere (2 birds), Tapapakanga (1 bird). Nearly all records (65%) were of birds heard rather than seen. Two pairs were seen.
During two weeks on the south-west Pacific islands of Wallis and Futuna in September-October 1993 I notes 24 of the 35 species of birds recorded by French ornithologists during a fuller survey in December 1985 and January 1986. A count of boobies on Futuna showed that 5% were adult Brown Boobies. Of the remainder, 27% were adult white morph Red-footed Boobies and 54% were adult Red-footed Boobies of the “white-tailed brown” morph. The continued presence of good numbers of Blue-crowned Lories on Futuna may indicate a lack of ship rats.
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.
Kiwi distribution in Northland was surveyed during 1992, largely by listening for calls. Kiwi were recorded at 242 sites in six Ecological Districts. High call rates were recorded in the central and northern parts of Northland in forest remnants of varying sizes, but remnants over 100 ha had significantly higher call counts. Kiwi have declined in abundance and range in southern Northland since the late 1970s. Threats and potential threats to Northland kiwi include habitat destruction and deterioration, but particularly predation by dogs and other introduced mammals.
Observations of birds were made while working on fishing trawlers intermittently for a total of almost a year in New Zealand subantarctic waters. Large numbers of several species of albatrosses and petrels are attracted to trawlers to scavenge and their numbers vary throughout the year. Species not attracted are seen less commonly. Scavenging behaviour around trawlers is discussed. There seems to have been an increase in scavenging by certain species in the last 30 years.
There are major sexual differences in the calls of Thin-billed Prion Pachyptila belcheti. This allowed birds to be sexed initially by calls, and then by their measurements. Males were on average larger than females for six out of eight morphometric characters, with the greatest difference being in the bill. We then investigated the possibility of sexing birds on the basis of external measurements: a discriminant function analysis based on the eight measurements allowed correct classification of 84.4% of the 281 birds. In 89% of breeding pairs, males had greater bill depth than their partner. A stepwise discriminant analysis revealed that bill depth, head length and body weight were the three most discriminant variables. The combinations of two measurements (bill depth and body weight, or bill depth and total head length) allowed correct classification of 84.3 and 83% of the birds respectively, whilst a classification solely based on bill depth gave a 83.2% correct classification. The degree of sexual dimorphism in this species is similar to that found in other tubenoses.