While we haven't observed an attack, we've observed the killer whales feeding on 3 different gray whale calves on different days and in different locations. (blueoceanwhalewatch.com)
Since April 19th there have been eight confirmed attacks on gray whale calves, two of which escaped predation. (blueoceanwhalewatch.com)
A pod of killer whales hunted their fourth gray whale calf in seven days. (sfgate.com)