Sticky substance is green, with something served as starter (8)
I believe the answer is:
birdlime
'sticky substance' is the definition.
(substance used to trap birds)
'green with something served as starter' is the wordplay.
I cannot quite understand how this works, but
'green' could be 'lime' (I've seen this before) and 'lime' is located in the answer.
The remaining letters 'bird' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'is' acts as a link.
(Another definition for birdlime that I've seen is " Sticky substance set to trap birds".)