Track is small and meagre (5)
I believe the answer is:
spoor
'track' is the definition.
(track left by an animal)
'small and meagre' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'and' says to put letters next to each other.
'meagre' becomes 'poor' (I've seen this before).
's'+'poor'='SPOOR'
'is' is the link.
(Other definitions for spoor that I've seen before include "Animal's track or scent" , "Track of wild animal" , "Animal's track/scent" , "Beast's trail" , "Animal track or scent" .)