The pair-bonding, recognition, defence, and courtship behaviour of the Magellanic cormorant (Phalacrocorax magellanicus) is described. Its displays indicate that its closest relatives are the pelagic and red-faced cormorants of the North Pacific, and that its similarities to the guanay (P. bougainvillii) are only superficial. The affinities of the Magellanic cormorant appear to lie with the cliff shags as a member of the Stictocarbo complex, rather than with the blue-eyed shag (Leucocarbo) complex.