Two birds seen at dawn (8)
I believe the answer is:
cockcrow
'at dawn' is the definition.
'cockcrow' can be an answer for 'dawn' (synonyms). I'm unsure of the 'at' bit.
'two birds' is the wordplay.
'two birds' can mean two substitutions for 'bird'.
'bird' becomes 'cock' (cock is a kind of bird).
'bird' becomes 'crow'.
'cock'+'crow'='COCKCROW'
'seen' is the link.
Can you help me to learn more?
(Other definitions for cockcrow that I've seen before include "first thing?" , "Dawn as signalled by rooster" , "Break of day" , "Dawn as signalled by farmyard fowl (4.4)" , "Dawn as announced by farmyard fowl" .)