Bird changes colouring (9)

I believe the answer is:

turnstone

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

'changes colouring' is the wordplay.
'changes' becomes 'turns' (turn is a kind of change**).
'colouring' becomes 'tone' (tone is a kind of colouring).
'turns'+'tone'='TURNSTONE'

(Other definitions for turnstone that I've seen before include "Sort of sandpiper" , "Wader" , "Shore bird" , "Small short-billed sandpiper" , "Flier" .)

I've seen this clue in The Independent.

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