High-flier in Tory party close to donor (6)
I believe the answer is:
condor
'high-flier' is the definition.
(type of bird)
'tory party close to donor' is the wordplay.
'tory' becomes 'con' (abbreviation for conservative).
'party' becomes 'do' (do is a kind of party).
'close to' says to take the final letters (the 'close' to the word).
The final letter of 'donor' is 'r'.
'con'+'do'+'r'='CONDOR'
'in' acts as a link.
(Other definitions for condor that I've seen before include "Large flyer" , "Andean bird" , "Large vulture of S America" , "Largest New World vulture" , "Large bird of prey" .)