Possible Clues:

• Type of captive
• Person held in empty edifice receiving bird
• Prisoner's nice warm coat, perhaps sleeveless
• Prisoner put under obligation briefly
• One imprisoned during wartime
• Camp dweller
• Houseman, English, twice confined suspected terrorist
• Painter needlessly includes one in confinement …
• Seabird captured in cold season not showing wings: one’s caged as a precaution
• Bury her as she was born and shut up