The Little Penguin Eudyptula minor in Victoria, II: Breeding

Abstract

Little Penguins were studied in the main breeding colony at Phillip Island, Victoria, on weekly and, later, monthly visits during eleven years. The birds were present all the year but numbers built up towards the onset of the breeding season, showing a three-week cycle of attendance. Breeding numbers varied slightly from year to year with a more marked drop in 1978 and perhaps 1973. The timing of breeding also differed from year to year, varying within a year and from year to year much more than in other seabirds of temperate latitudes.

Study of breeding success showed that on average August to November each produced about the same number of young, though in any one year these could be differences between these months. There were individual differences in breeding efficiency associated with the length of time a bird was recorded in the area. These reflected differences in in- dividual 'quality' rather than in age or experience.

Pair bonding and divorce are described. Birds that had bred before and changed mates nested earlier in the next season than they did in the previous season with the old mate. Failure to breed by adults was exceptional but may occur in some years. Few birds banded as chicks have been found breeding but those that have have apparently been at least three or four years old. There were some marked differences between the breeding of the species at Phillip Island and in Tasmania.

Various features of the breeding of the Little Penguin are considered from the point of view of strategies to enhance reproductive success: choice of burrow, size of clutch, age of first breeding, pattern of pair bonding, timing of the breeding season. Regarding the last, the population on Phillip Island is intermediate between 'typical' penguins of polar and sub-polar regions and those of some of the tropical genus Spheniscus, which show opportunistic breeding throughout the year.