Bird from banks of Amazon to keep passing through (5)
I believe the answer is:
avian
'bird' is the definition.
'banks of amazon to keep passing through' is the wordplay.
'banks of' means to remove the middle letters (the banks are the sides of the word).
'to keep' indicates putting letters inside.
'passing through' becomes 'via' (I've seen this before).
'amazon' with its centre taken out is 'an'.
'an' going around 'via' is 'AVIAN'.
'from' acts as a link.
(Other definitions for avian that I've seen before include "Like a booby" , "Like rails, for example" , "Lizard with adhesive foot-pads" , "Pertaining to or characteristic of birds" , "Regarding birds" .)