The smallest of the three endemic New Zealand teal species. Small, flightless dark brown duck. Males have green iridescence on head and dark chestnut-colored breast. Females are uniformly dark brown. Both sexes show bold white eye-ring. More secretive than the closely related Auckland Islands Teal; most often found on the shoreline foraging through piles of seaweed or rocks. Also can be found on peaty streams or in wetland pools with adequate cover from sedges and tussock. Confined to Campbell Islands other than an introduction on Codfish Island, where a small population remains. Males give a soft trill as an alarm or territorial call. Females give a growl and a rapid quack. Distinguished from other New Zealand endemic teal species by location and more prominent white eye-ring.