Anas chathamica, the Chatham duck or Chatham Island duck is an extinct species of duck which once lived in New Zealand's Chatham Islands in the south-west Pacific Ocean. It likely became extinct in about the 16th century because of hunting by humans.[1]
The species was formerly placed in a monotypic genus Pachyanas. However, analysis of mitochondrial DNA extracted from subfossil remains[2] showed that the Chatham duck was not, in fact, closely related to shelducks but instead belongs in the genus Anas: the dabbling ducks. Its closest living relatives appear to be the Auckland teal, Campbell teal and the brown teal from New Zealand.
It was described by Walter Oliver (as a "stoutly built duck") from bird bones in the collection of the Canterbury Museum in 1955 in the second edition of his work New Zealand Birds.[3] Some authors have suggested that the Chatham duck was flightless;[4] however, comparison of Chatham duck wing bones with those from living ducks indicates no disproportional reduction in wing length.[2]