### Clue: Gloria's great at the final curtain (8)
### Answer: SWANSONG 
 ### Explanation: Definition: final curtain
 SWANSON(Gloria, American film actress) + G(abbrev. for "great", as in GB for Great Britain, but I'm not sure about when it's a standalone).
And this quip from S.T. Coleridge (he who wrote a much longer verse featuring another bird):
Swans sing before they die— 't were no bad thing
Should certain persons die before they sing.