Eventually the parent never looks back, plunging into the sea to fetch more food. Some experts have suggested that the chases help parents ration limited food supplies. Instead, Boersma guessed that the zigzag maneuvers would give the weaker chick a chance to get a beakful of krill without the stronger one on its tail. To test that idea, she and her colleague, Lloyd Davis of the University of Otago in New Zealand, observed interactions between parents and young on Ross Island in the Antarctic. Just as predicted, the chases increased the likelihood that the weaker chick got its share.
Experts say the study finally sheds light on one Antarctic mystery.