Possible Clues:

• Bird on a train?
• Traveller taking responsibility for vanished bird
• Craft seen with ageing props — it's no longer flying
• Bird named for its large-scale migrations
• Old bird pens going spare, distributed with energy
• Extinct migratory bird
• Patsy, to a cab driver?
• Old commuter bird?
• Fare a particular concern for long-distance flyer