Evoke birdsong, not one of the top three we hear (4,5)
I believe the answer is:
call forth
'evoke' is the definition.
(synonyms)
'birdsong not one of the top three we hear' is the wordplay.
'birdsong' becomes 'call' (synonyms).
'not one of the top three' becomes 'fourth' (in fourth place).
'we hear' shows a homophone (sound like).
'fourth' sounds like 'forth'.
'call'+'forth'='CALL FORTH'
(Other definitions for call forth that I've seen before include "Summon" , "Evoke" .)