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Chick production at the largest emperor penguin colony decreases by 50% from 2008–10

Published online by Cambridge University Press:  18 July 2013

G.L. Kooyman*
Affiliation:
Scholander Hall, Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, La Jolla, CA 92093, USA
P.J. Ponganis
Affiliation:
Scholander Hall, Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, La Jolla, CA 92093, USA

Abstract

The emperor penguin colony at Coulman Island is reputedly the largest known. This reputation is based on intermittent ground and aerial surveys performed since 1958. From an aerial survey obtained on 28 October 2010 we discovered that the total number of chicks was 56% of the lowest previous estimate of 2006 and only 41% of the most recent estimate in 2008. All of the counts tallied since 1983 were determined either by ground counts or from aerial film or digital photographs, or estimates from adult counts. We also determined the sea ice conditions in autumn, which is close to the time the adults arrive to breed. We present three hypotheses of what might have happened from 2008–10 to cause the step change in chick production, the small recovery of chick numbers in 2011, and the complete recovery of number of adults from 2010–11. We conclude that local circumstances may have strongly influenced the breeding behaviour of the emperor penguins in 2010 and to a lesser degree in 2011 when many adults elected not to breed.

Type
Biological Sciences
Copyright
Copyright © Antarctic Science Ltd 2013 

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