See bird, for example, flying north (3,2)
I believe the answer is:
get it
'see' is the definition.
(to get something is to see or understand it)
'bird for example flying north' is the wordplay.
'bird' becomes 'tit' (tit is a kind of bird).
'for example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'flying north' says the letters should be written in reverse (in a down clue, letters go up or \'north\').
'tit'+'eg'='titeg'
'titeg' written backwards gives 'GET IT?'.
(Other definitions for get it that I've seen before include "twig?" , "Be punished" , "Understand" , "See the point" .)