Extremely clumsy snare trapping tail of young bird (6)
I believe the answer is:
cygnet
'bird' is the definition.
(cygnet is a kind of bird)
'extremely clumsy snare trapping tail of young' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'snare' becomes 'net' (I've seen this in another clue).
'trapping' indicates putting letters inside.
'tail of' says to take the final letters.
'clumsy' with its middle removed is 'cy'.
The final letter of 'young' is 'g'.
'cy'+'net'='cynet'
'cynet' placed around 'g' is 'CYGNET'.
(Other definitions for cygnet that I've seen before include "Young water-bird" , "Immature swan" , "Young bird of a particular type" , "that's no ugly duckling" , "Small pen, perhaps?" .)