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The size and breeding patterns of Little Penguins Eudyptula minor in Australia: A comparative study

Wienecke, Barbara C. (1993) The size and breeding patterns of Little Penguins Eudyptula minor in Australia: A comparative study. PhD thesis, Murdoch University.

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Abstract

The breeding regime of Little Penguins Eudyptula minor was studied on Penguin Island, Western Australia, from January 1990 to December 1992. Data from 1986 to 1989 were also available for analysis. Little Penguins at Penguin Island laid eggs over a very protracted period, which commonly extended from late April to early November. Two peaks of laying occurred in several of the years studied. The onset of first laying was strongly influenced by temperatures over 30° C but was independent of breeding success in the previous season. Body condition in adults was correlated with total rainfall, possibly through storm events.

The sizes and weights of eggs did not differ significantly between years nor differ between the first and second eggs in a clutch. The numbers of eggs which hatched and the numbers of chicks which fledged varied significantly between years. Overall breeding success was less than 50 % (21 - 48 %). On average, each breeding adult produced 0.48 young per year.

Annual survival of adults was estimated as 75 % giving an average breeding life time of 4.8 years. Of those banded as chicks, 67.5 % returned at two or three years old. Banding recoveries were up to 283 km distant but 69 % were within 10 km of the colony.

Significantly more individuals returned to the same nest when they remained with the same partner and when they bred successfully in the previous year.

Growth constants of chicks did not differ significantly between years or between first and second chick in a brood. The tarsus grew faster than the flipper and beak.

Morphometric analyses showed that Little Penguins from Penguin Island arid the White-flippered Penguins from New Zealand both to be larger than Little Penguins from Tasmania and the eastern mainland of Australia. The most similar, morphometrically, were those at Jarvis Bay, Phillip Island, Tasmania and Albany. Comparison of DNA of Little Penguins appeared to support this scenario although genetic results are necessarily tentative due to the small sample sizes.

Item Type: Thesis (PhD)
Murdoch Affiliation: School of Veterinary Studies
Notes: Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: repository@murdoch.edu.au. Thank you.
Supervisor(s): Wooller, Ron and Bradley, Stuart
URI: http://researchrepository.murdoch.edu.au/id/eprint/53080
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