Codfish Island Survey 2009

The population census of yellow-eyed penguins in the Stewart Island area was completed in November 2009 when the last remaining area to be surveyed, Codfish Island/ Whenua Hou, was visited. Last surveyed fully in 2001, Codfish Island / Whenua Hou is considered one of the strongholds of the Stewart Island penguin population and has been one of the study sites for the Trusts 2003-2008 research into factors affecting penguin breeding success. Two of the original surveyors, Dave Houston and Dean Nelson from DOC, and Sandy King from the Trust made up the 2009 survey team, with help from resident Kakapo Rangers Errol & Steve. The survey was completed within a week and found 46 breeding pairs, a drop from 61 breeding pairs in 2001. This could be a real downwards trend, or it could be just an extreme interannual fluctuation, but to find out more regular surveys and monitoring will be required. The Trust is working with DOC and the Southern Institute of Technology to ensure this can happen.

The Trust’s study has shown that breeding success on Codfish Island / Whenua Hou has generally been good, and a recent follow-up visit has shown that this season is no exception. From 4-10^th February 2010 all nest sites found in November 2009 were checked to assess breeding success. 54 chicks were caught, weighed and measured, given a health check, and had a microchip inserted just under the skin on the back of their neck. Microchipping will enable individual birds to be identified in future, which in turn will provide information about juvenile and adult survival and recruitment. Most of the chicks caught were in good condition; the median weight was 5.15kg and weights ranged from 2.3-6.3kg. Overall breeding success was 58%, with each nest producing an average of 1.15 chicks.

Related posts:

• Codfish Island Survey
• Codfish Island
• Unexplained Chick Losses on Stewart Island
• Auckland Island Survey Blog
• Cat predation on Stewart Island