Large bird sadly swallows pet rook (8)

I believe the answer is:

alcatras

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'large bird' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'sadly swallows pet rook' is the wordplay.
'sadly' becomes 'alas' (I've seen this before).
'swallows' means one lot of letters goes inside another.
'pet' becomes 'cat' (I've seen this in other clues).
'rook' becomes 'r' (abbreviation in chess).
'cat'+'r'='catr'
'alas' enclosing 'catr' is 'ALCATRAS'.

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