Possible Clues:

• Program that mimics the Atari 2600, e.g
• Person copying another
• Oz runner eventually caught rival
• One who will mimic flightless bird audibly by and by
• Bird approaches hill behind American city with mimic
• He copies bird's Latin listing -- that will be shown up
• Rival, perhaps
• Amulet or another one that matches
• One copies the behaviour of another
• Imitator