Chatham Island merganser
The Chatham Island merganser or Chatham merganser is an extinct species of merganser duck.
The Chatham Islands merganser is known only from fossils and not much is known about the bird. It was the smallest of all Mergus species. Fossil records indicate it was widespread on Chatham Island but not on the smaller nearby islands.
The binomial name refers to Dr Philip Millener, to recognise his work in collecting material on the species.