Bird Conservation International


Differences in the digestive organ morphology of captive and wild Brown Teal Anas chlorotis and implications for releases

a1 Ecology Group, Massey University, Private Bag 11 222, Palmerston North, New Zealand
a2 Department of Mathematics and Statistics, University of Otago, P. O. Box 56, Dunedin, New Zealand. E-mail:

Article author query
moore sj   [PubMed][Google Scholar] 
battley pf   [PubMed][Google Scholar] 


The digestive tract of many animals is morphologically flexible and can adjust over time to make the most efficient use of the foods available. Differences between captive and wild diets often cause large differences in the gut morphology of captive and wild birds. This is potentially an issue when captive-bred birds are used to establish or supplement populations in the wild, such as in the Brown Teal Anas chlorotis, an endangered duck endemic to New Zealand. We compared the size and mass of the digestive organs (proventriculus, gizzard, small intestine, caeca, rectum and liver) of 57 wild, eight captive and four captive-bred released Brown Teal. Captive Brown Teal had much shorter and lighter small intestines and caeca than wild Brown Teal. These differences could reduce the ability of captive-bred teal to efficiently digest a wild diet in the weeks following release, and are likely to contribute to the number of released teal found dead in extremely poor nutritional condition. Increased fibre and diversity in the captive diet together with supplementary feeding post-release are recommended to improve the survival of captive-bred Brown Teal released to the wild.

(Published Online July 31 2006)
(Received April 27 2005)
(Accepted September 26 2005)

p1 Current address: P. O. Box 151, Tuakau, New Zealand. E-mail: