Little bird of woodland leaving egg, tawny primarily (5)
I believe the answer is:
owlet
'little bird' is the definition.
(I've seen this before)
'of woodland leaving egg tawny primarily' is the wordplay.
'of' becomes 'o''.
'primarily' indicates taking the first letters.
The initial letters of 'woodland leaving egg tawny' is 'wlet'.
'o'+'wlet'='OWLET'
(Other definitions for owlet that I've seen before include "Young bird; moth" , "One may give a little screech" , "Young nocturnal hunting bird" , "Little nocturnal bird" , "Towel (anag)" .)