Related Clues:

• At the ready
• Far from sleepy
• Bright-eyed and bushy-tailed
• Advance warning
• Watching
• Quick on the uptake
• Attentive
• With ears pricked
• Not nodding
• Red flag, e.g.
• Prepared for action
• Caffeinated?
• Ready for deployment
• Trouble indicator
• Not dozing