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Population size, breeding, and annual cycle of the New Zealand Antarctic tern ( Sterna vittata bethunei ) at the Snares Islands

Notornis, 50 (1), 36-42

P.M. Sagar; C.M. Miskelly; J.L. Sagar; A.J.D. Tennyson (2003)

Article Type:

The population size, breeding, and annual cycle of Antarctic terns (Sterna vittata bethunei) at the subantarctic Snares Islands were studied intermittently from 1976 to 2002. During the 1983/84 and 1984/85 breeding seasons the population comprised a minimum of 65 breeding pairs. Laying dates extended from mid Sep to late Mar, with peak laying in late Oct-early Nov. Clutch size averaged 1.33 (range 1-2 eggs) and did not change through the breeding season. Both parents incubated. Hatching success was 92.7% and both parents fed the young. Fledging success was 75%, and so overall breeding success was 69.6%. Chicks were fed mostly fish by both parents and 1-chick broods were fed smaller fish and less frequently than 2-chick broods. The youngest bird recorded breeding was at least 3 years old. After the breeding season (from Mar), the terns formed flocks and moulted in the vicinity of the Snares Islands. Following the completion of moult (from Apr) they tended to move offshore, only returning to the shelter of the islands during severe weather. From mid Jul, the terns tended to roost in flocks at the Snares Islands before dispersing to form pairs and defend nesting sites.

The yellow-eyed penguin ( Megadyptes antipodes ) on Stewart and Codfish Islands

Notornis, 50 (3), 148-154

J.T. Darby (2003)

Article Type: paper

Recent estimates of the number of yellow-eyed penguin (Megadyptes antipodes) throughout its range have led to a revised figure for the total population of this species. The number of breeding pairs on Stewart and Codfish Is together with the Auckland Is remain the least well known. Ground searches in 1984 -1994 on Stewart and Codfish Is suggested fewer birds than expected. The results of 102 ground searches of 61 localities and 118 beach counts (>700 h of observations) support a lowering of earlier estimates to c. 170-320 pairs on Stewart Is and its outliers, and 50-80 breeding pairs on Codfish Is, giving a total of 220-400 pairs for this region. The relatively few breeding pairs found on Stewart Is, based on the length of coastline and hinterland area available, together with the small groupings, suggest that predation of adults and chicks may be a factor in the relatively low numbers of this species on Stewart Is itself.

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