Young bird caught by good trap — finally flying into it (6)
I believe the answer is:
cygnet
'young bird' is the definition.
(young swan)
'caught by good trap finally flying into it' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'by good' becomes 'y' (I can't justify this - if you can you should give a lot more credence to this answer).
'trap' becomes 'net' (net is a kind of trap).
'finally' says to take the final letters.
'into it' means one lot of letters goes inside another.
The last letter of 'flying' is 'g'.
'y'+'net'='ynet'
'ynet' placed around 'g' is 'ygnet'.
'c'+'ygnet'='CYGNET'
(Other definitions for cygnet that I've seen before include "that's no ugly duckling" , "Young bird of a particular type" , "Sounds like the type of ring" , "Little swan" , "Young water-bird" .)