Part of plant or insect or bird (9)
I believe the answer is:
cormorant
'bird' is the definition.
(cormorant is a kind of bird)
'part of plant or insect' is the wordplay.
'part of plant' becomes 'corm' (type of stem part on some plants).
'insect' becomes 'ant' (ant is a kind of insect).
'corm'+'or'+'ant'='CORMORANT'
'or' is the link.
(Other definitions for cormorant that I've seen before include "Diving coastal bird" , "Black/white fish eater" , "Large voracious sea bird" , "Proverbially gluttonous seabird" , "Aquatic bird" .)