Examining bird admitted by doctor turning up (7)
I believe the answer is:
probing
'examining' is the definition.
('probe' can be a synonym of 'examine')
'bird admitted by doctor turning up' is the wordplay.
'bird' becomes 'robin' (robin is a kind of bird**).
'admitted by' is an insertion indicator.
'doctor' becomes 'gp' (general practitioner).
'turning up' says the letters should be written backwards.
'gp' written backwards gives 'pg'.
'robin' put within 'pg' is 'PROBING'.
(Other definitions for probing that I've seen before include "Testing" , "Investigating - prodding" .)