[4] The species was possibly once the most common duck in New Zealand, a supposition based on the frequency of its fossils in bone deposits.

Finsch's duck was scientifically described as Anas finschi in 1876 by Pierre-Joseph van Beneden.

The specific epithet finschi and the common name honours ornithologist Otto Finsch, who first recognised it as a distinct species.

The wings were much reduced however, and it seems that flight was lost relatively quickly after the species arrived in New Zealand.

Finsch’s duck was most likely a grazer and browser of vegetation, probably mixed with fallen fruit and some invertebrates.