Found truck following popular small bird (9)
I believe the answer is:
institute
'found' is the definition.
(thesaurus)
'truck following popular small bird' is the wordplay.
'truck' becomes 'ute' (Australian abbreviation for utility vehicle).
'following' says to put letters next to each other.
'popular' becomes 'in'.
'small' becomes 's' (abbreviation - e.g. clothes size).
'bird' becomes 'tit' (I've seen this before**).
'in'+'s'+'tit'='instit'
'ute' put after 'instit' is 'INSTITUTE'.
(Other definitions for institute that I've seen before include "Educational organisation, found or begin one" , "Scientific, educational or social organisation" , "asylum, possibly?" , "Set in motion, establish" , "Found; an establishment" .)