Little bird — one finally given tag (6)

I believe the answer is:

eaglet

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'little bird' is the definition.
(I've seen this before)

'one finally given tag' is the wordplay.
'finally' says to take the final letters.
'given tag' becomes 'aglet' (I can't justify this - if you can you should believe this answer much more).
The final letter of 'one' is 'e'.
'e'+'aglet'='EAGLET'

Can you help me to learn more?

(Other definitions for eaglet that I've seen before include "Young lawyer" , "A young raptor" , "Get ale for the young bird" , "Eyrie resident" , "Young keen-sighted bird" .)

I've seen this clue in The Guardian.

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