Bird collecting article from another planet (7)
I believe the answer is:
martian
'from another planet' is the definition.
(from Mars)
'bird collecting article' is the wordplay.
'bird collecting' becomes 'marti' (I can't explain this - if you can you should give a lot more credence to this answer).
'article' becomes 'an' (indefinite article).
'marti'+'an'='MARTIAN'
Can you help me to learn more?
(Other definitions for martian that I've seen before include "Sci-fi alien" , "One of H. G. Wells's invaders" , "One living on red planet" , "seeing little green man?" , "Being from another planet" .)