Dead bird boy finds outside (8)
I believe the answer is:
external
'outside' is the definition.
('external' is associated in meaning with 'outside')
'dead bird boy' is the wordplay.
'dead' becomes 'ex'.
'bird' becomes 'tern' (tern is a kind of bird**).
'boy' becomes 'al'.
'ex'+'tern'+'al'='EXTERNAL'
'finds' is the link.
(Other definitions for external that I've seen before include "Lying outside" , "Outer" , "Superficial" , "Coming from outside" , "abroad" .)