The bird on the wharf (6)

I believe the answer is:

canary

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'the bird' is the definition.
(canary is a kind of bird)

I don't understand how the rest of the clue works.

(Other definitions for canary that I've seen before include "a sort of finch" , "Bright yellow shade" , "Type of finch" , "Songbird once used to detect toxic gases in mines" , "grass" .)

I've seen this clue in the Evening Standard.

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