Such a pigeon comes down to earth (4)
I believe the answer is:
clay
'earth' is the definition.
(clay is a kind of earth)
'such a pigeon comes' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
The remaining letters 'cly' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'down to' is the link.
Can you help me to learn more?
(Other definitions for clay that I've seen before include "Human body" , "Moulding material" , "Earthenware" , "Soil for moulding" , "Wet, fine-grained earth" .)