Related Clues:

• Bittersweet performance
• Farewell appearance
• Farewell performance
• Final performance
• Concluding appearance
• Bittersweet farewell
• A last performance, as of noble bird
• Last act or work, as of noble bird
• Bird music for last act before death or retirement
• Final performance, last hurrah
• Last act before death, like noble white bird
• Final performance, as the air of an aquatic bird
• That's the very last thing you'd expect from 15 across, by the sound of it
• One might perhaps, have a penchant for this at last
• The sort of 23 down that's the last thing you'd expect from the bird