Publications Archive

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.

In 1989, 4194 kilometres of coast of New Zealand were patrolled and 8221 dead seabirds were found as part of the Beach Patrol Scheme. Unusual finds were a Snares Crested Penguin (Eudyptes robustus), two White-capped Noddies (Anous tenuirostris minutus) and a Brown Booby (Sula serrator leucogaster). A summary is given of the coastal and monthly distributions of Pelecanoides, Phaethon and Fregata species found during the 1943-1988 period. Overall, 11 472 Pelecanoides urinatrix were found, but 10 or fewer of the other three species were found.

We assessed the numbers, distribution, and habitat of Bristle-tithed Curlews (Numinous tahitiensis) on Rangiroa Atoll, Tuamotu Archipelago, during a visit in April 1988. We estimated a total of 250-350 curlews on the atoll. These birds were seen only on the southern and western rims, where they were most common on (1) saltpans within clusters of small islets and (2) narrow channels between islets that were bordered by shrubs and herb mats. The distribution of curlews on Rangiroa appeared to be determined by the distribution of humans and their commensal animals and by the availability of habitats. Given the species’ relatively low numbers, low reproductive rate, and prebasic moult which, for some adults, entails a flightless period, conservation and management efforts must begin on the non-breeding grounds. These efforts should focus on reducing or eliminating potential mortality factors such as subsistence harvest, introduced predators, and contaminants. Countries throughout the species’ non-breeding range are encouraged to be active in these efforts.

In a 20-year nest box study of Starlings (Sturnus vulgaris) in New Zealand, intraspecific fighting was the main mortality factor recorded. All fights were between birds of the same sex, 24 male-male and 22 female-female, and most were in the breeding season. Fighting increased as the population rose from about 300 birds in 1969 to over 3000 after 1978. Because of the low annual mortality rate of Starlings in New Zealand (330/0), the chances of ever breeding were small for many birds. Hence conditions were ideal for a high level of fatal fighting, which took the form of grasping the opponent round the head so that the claws penetrated the brain through the eye sockets.