Bird on a Canadian $1 coin (4)
I believe the answer is:
loon
'bird on a canadian $1 coin' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for loon that I've seen before include "Simple-minded person" , "Noddy" , "Fool" , "Diving bird with wild cry - sounds crazy" , "Fish-eating diving bird" .)