In 1991, 4780 km of coast of New Zealand were patrolled and 6955 dead seabirds were found as part 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.
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 (Sturnus 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.
Between 1988 and 1992, we conducted the first comprehensive survey of the number and breeding distribution of the New Zealand dotterel (Charadrius obscurus) on Stewart Island. The population forms three post-breeding flocks, two of them on Stewart Island; band sightings have confirmed an earlier suggestion that the flock at Awarua Bay, Southland, is also composed of birds from the island. The population is widely spread over difficult terrain during the breeding season; autumn counts of the flocks provide the only practical means of assessing population size. Comparisons with earlier counts show that the population has declined to about one-fifth of its former size in the past 37 years The population is critically endangered because the decline continues and only 60-65 dotterels remain. Average annual mortality of banded adults between 1990 and 1992 was 23%. The major reason for the decline is believed to be predation by feral cats. Band sightings suggest that, apart from Southland, most or all of the recent NZ Dotterel records from the South Island coast (including Farewell Spit) are of juveniles wandering from Stewart Island.
Potential relationship between meteorological conditions and the timing and path of cattle egret migration from colonies in the Hunter Valley (NSW) to locations in Victoria, Tasmania and New Zealand were investigated for the period 1987-1989. Meteorological maps obtained for a period of up to five days previous to known movement dates were analysed to identify possible migration paths. Three potential outward and two potential return paths were identified which make use of wind-flows around high and low systems. The results show that cattle egrets may well utilise weather systems in their migration and point to the need for further research for clarification.
The seasonal change in yellow-eyed penguin numbers using a landing site (or part of the beach where penguins moved to or from the sea) at Middle Bay, Campbell Island, was monitored between November 1987 and September 1988. Numbers were low during the incubation phase of nesting (November) and rose to a peak during the chick-rearing period (December-March) when most breeding birds were travelling to sea each day. Numbers were low during the moult (April) as most birds were ashore. Peak numbers occurred in May but declined subsequently because of sea lion disturbance and pre-breeding behaviour. A census of 172 landing sites on Campbell Island during May-July 1988 found 1625 penguins, which may have represented a total of 2000 birds, or 490-600 breeding pairs. Decreases in penguin numbers at several landing sites between 1988 and 1990 suggest the population may have declined by about 45%. A census of 115 landing sites on part of the Auckland Islands in November-December 1989 found 934 penguins, which may have represented a population of 420-470 breeding pairs. Allowing for a possible sparse population on the east coast of Auckland Island, 520-570 pairs is a very conservative estimate for the islands. The total yellow-eyed penguin population in 1988-1989 was approximately 5930-6970 birds, with at least 56% in the subantarctic.