Visitor stumped nature reserve official (8)

I believe the answer is:

stranger

'visitor' is the definition.
(I've seen this before)

'stumped nature reserve official' is the wordplay.
'stumped' becomes 'st' (I've seen this in other clues).
'nature reserve official' becomes 'ranger'.
'st'+'ranger'='STRANGER'

(Other definitions for stranger that I've seen before include "More odd or unknown" , "Unfamiliar person" , "More odd or wierd" , "Odder, more peculiar" , "Person one is not acquainted with" .)

I've seen this clue in The Telegraph.

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