A pig eats young salmon and small bird (7)
I believe the answer is:
sparrow
'small bird' is the definition.
(type of bird)
'a pig eats young salmon' is the wordplay.
'a pig' becomes 'sow' (I've seen this in another clue).
'eats' is an insertion indicator.
'young salmon' becomes 'parr' (I've seen this before).
'sow' placed around 'parr' is 'SPARROW'.
'and' acts as a link.
(Other definitions for sparrow that I've seen before include "bird produced" , "Who killed Cock Robin" , "fowl, using outdated term" , "Cock Robin's assassin" , "House bird" .)