I'm surprised Mike's old crosswords mentioned something like 'shag' (9)

I believe the answer is:

cormorant

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'crosswords mentioned something like shag' is the definition.
I can't judge whether this defines the answer.

'i'm surprised mike's old' is the wordplay.
'i'm surprised' becomes 'cor' (old-fashioned UK expression of shock or awe).
'mike' becomes 'm' (phonetic alphabet: alpha, bravo, charlie etc.).
'old' becomes 'orant' (I can't explain this - if you can you should give a lot more credence to this answer).
'cor'+'m'+'orant'='CORMORANT'

Can you help me to learn more?

(Other definitions for cormorant that I've seen before include "Large, long-necked seabird" , "Black/white fish eater" , "Diver" , "Glutton" , "High-flier" .)

I've seen this clue in The Independent.

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