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. oridiformis 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.
In a 1-day study of the Australian Coot (Fulica atra australis), the duration of dives increased with increasing depth, although the frequency of diving remained relatively constant. Duration and frequency of dives at given depths appeared not to vary with age. However, aggressive adults often drove young birds into deeper water. The duration of dives changed with the time of day, the birds preferring to dive in direct sunlight.
In 1991, 4780 km of coast of New Zealand were patrolled and 6955 dead seabirds were found as pan of the Beach Patrol Scheme. An unusual find was a Red-tailed Tropicbird (Phaethon rubricauda), and more than usual were found of the Antarctic Petrel (Thalassoica antarctica), White-headed Petrel (Pterodroma lessonii), Little Black Shag (Phalacrocorax sulcirostris) and Brown Skua (Catharacta skua lonnbergi). A summary is given of the coastal and monthly distributions of Morus and Sula species found during the 1943-1991 period. Overall, 5637 Australasian Gannets (Morus serrator) were found, mainly on beaches of the northern half of the North Island. The peak period of adult recoveries was in December-February, but that of juveniles was in February-May. Both the Brown Booby (Sula leucogaster) and the Masked Booby (Sula dactylatra) are vagrants to the New Zealand mainland, with four and one individuals respectively having been found by patrollers.
G.R. Gray first used the name Pelecanus serrator in association with the drawing by Sydney Parkinson of an adult Australasian Gannet taken at sea near the Three Kings Islands in 1769. Parkinson’s drawing is an illustration of the specimen described in manuscript by Daniel Solander as Pelecanus serrator. Both the drawing and the description are of the type specimen and have previously unrecognised taxonomic importance. The correct type locality of Morus serrator is the vicinity of the Three Kings Islands.
The Kakerori, or Rarotonga Flycatcher, of the Cook Islands has two distinctive colour forms: orange and grey. Our colour-band study showed that colour is simply related to age, not to sex as described earlier. When fledglings leave the nest their body is covered in grey down, and their wings and tail are still growing. Orange juvenal plumage is attained about one month after fledging. Despite having similar orange plumage, yearlings can be distinguished from 2 year-old birds on the basis of bill colour and wing and tail lengths. Third-year birds have elements of both main colour phases. Once the definitive basic plumage is attained in the fourth year, the age of grey birds cannot be determined. Wing and tail lengths apparently increase at each successive moult until the definitive basic plumage is reached. Males are larger than females, with bill length being the best discriminator. The progressive colour change recorded here parallels that described for three of the four other species of Pomarea flycatcher in eastern Polynesia, but colour variation in the other species, and in some other monarch flycatchers in the Pacific, needs critical examination. The ability to distinguish three cohorts of Kakerori is useful in measuring annual variations in productivity, survivorship, and age structure of the population.
Monthly bird counts were recorded for Kaikorai Estuary, Otago from July 1989 to June 1991. Fifty species were noted, including passerines on the estuarine fringe. The predominant species was the Southern Black-backed Gull (Larus dominicanus), which accounted for 61% of the birds surveyed. They overwhelmed the Dunedin City Council refuse up site at Green Island and, to a lesser extent, a tip in private use. Mallards (Anas platyrhynchos) and Starlings (Sternus vulgaris) were the next most common species. Numbers of birds decreased with distance from the tip sites but, conversely, the number of species increased. Numbers were highest in March-April, but declined rapidly by two-thirds to a July-August low. This decline was due to the dramatic fall in duck numbers with the opening of duckshooting season and to the onset of winter. The total annual count for the second half of the survey (July 1990 to July 1991) was 4% down on the previous 12 months, but this was not statistically significant.