Hit Detection question

programming flash
1

I’m making an educational side-scrolling game where basically one animal “eats” other aquatic animals on the stage. Right now, it counts as a hit when anywhere on the entire movieclip for the character (“char”) touches one of the prey. How do I make just the head count?

function preyHandler(event:Event)
            {// handler for prey getting eaten
                for (var i:int=0; i<allPrey.length; i++)
                {
                    if (event.target.hitTestObject(char))
                    {
                        //trace ("hit test successful");
                        event.target.width = 0;
                        event.target.height = 0;
                        preyCount++;
                        trace("score +1");
                        score.text = String(preyCount);

                        event.target.removeEventListener(Event.ENTER_FRAME, preyHandler);
                    }
                }
            }//end preyHandler

I made a clip inside “char” called “head” and tried

 if (event.target.hitTestObject(char.head))

and event just

 if (event.target.hitTestObject(head))

but those made crazy errors.

What is the correct way to do this? Any help appreciated.