Little bird sitting comfortably (8)
I believe the answer is:
nestling
'little bird' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for nestling that I've seen before include "getting under duvet?" , "Little bird" , "not yet put out" , "in a huddle" , "Young bird - snuggling" .)