Attempt, with catapult, to get young bird (7)
I believe the answer is:
gosling
'young bird' is the definition.
(I've seen this before)
'attempt with catapult' is the wordplay.
'attempt' becomes 'go' (go is a kind of attempt).
'with' is a charade indicator (letters next to each other).
'catapult' becomes 'sling' (synonyms).
'go'+'sling'='GOSLING'
'to get' acts as a link.
(Other definitions for gosling that I've seen before include "Young waterbird" , "Young goose" , "Young bird" , "Little bird" .)