Spot deer near mushrooms heading north (7)
I believe the answer is:
speckle
'spot' is the definition.
(speckling is a kind of spotting)
'deer near mushrooms heading north' is the wordplay.
'deer' becomes 'elk' (type of deer).
'near' says to put letters next to each other.
'mushrooms' becomes 'ceps' (cep is a type of mushroom).
'heading north' shows that the letters should be reversed in order (in a down clue, letters go up).
'elk'+'ceps'='elkceps'
'elkceps' in reverse letter order is 'SPECKLE'.
(Other definitions for speckle that I've seen before include "pepper with colour" , "Small mark on skin" , "Mark with small dots" , "Small spot of colour" , "Bespatter" .)