SURFACE-TENSION FEEDING IN PHALAROPES - DISCOVERY OF A NOVEL FEEDING MECHANISM

We report the discovery of a previously undescribed feeding mechanism in an avian planktivore, the Red-necked Phalarope (Phalaropus lobatus) . We employed high-speed video to elucidate the kinematics of prey tra nsport, and to test hypotheses generated by a model describing prey tr ansport as a function of surface tension. Prey items are transported i ndividually from the tip of the beak to the mouth by forces resulting from the surface tension of water surrounding prey. Experiments conduc ted with the beak of a dead bird demonstrate that surface tension is s ufficient to explain prey transport in Red-necked Phalaropes without t he use of suction or tongue motions. This feeding mechanism may be wid espread among the shorebirds and represents a potential intermediate s tep in the evolution of filter feeding in birds.