Patterns of nest relief during incubation,and incubation period variability in the yellow-eyed penguin (Megadyptes antipodes)

Abstract

Daily nest checks were used to determine the yellow-eyed penguin’s pattern of nest relief during incubation, and to examine the inter-pair variability in incubation period. Nests at two breeding areas on the Otago Peninsula were visited between September and December in 1985 and 1986. At each visit, status of the nest and the identity and behaviour of the sitting bird was recorded. Incubation is shared between the sexes, with males tending to sit longer than females. Incubation spells ranged from 1–7 days with a mode of 1–2 days. Records of lone incubation following mate death show the yelloweyed penguin to be capable of 15 day unrelieved spells at the nest The incubation period of the yellow-eyed penguin ranges from 39–51 days and is the most variable of all penguins. This variability is because of the failure of some individuals to adequately cover the clutch until up to 5 days after the laying of the second egg.