Moore and Battley (2003): Cockle-opening by a dabbling duck, the Brown Teal.

Moore, S.J. & Battley, P.F. 2003. Cockle-opening by a dabbling duck, the Brown Teal. Waterbirds 26: 331-334.

Many birds feed on bivalves, but only oystercatchers (Haematopus spp.) are known to prise open the shells. Brown Teal (Anas chlorotis), a dabbling duck endemic to New Zealand, were observed opening Common Cockles (Austrovenus stutchburyi) on Great Barrier Island. The teal jack-hammered into the open shells of feeding cockles and quickly scooped out the flesh. Despite having the bill morphology of a typical dabbling duck, they were adept at this feeding method.