Starting point by way of Pole, like a bird (5)
I believe the answer is:
avian
'like a bird' is the definition.
(I've seen this in another clue)
'starting point by way of pole' is the wordplay.
'starting point' becomes 'a' (as in the phrase 'get from A to B').
'by way of' becomes 'via' (via means by way of or by means of).
'pole' becomes 'n' (abbreviation for North, as in North Pole).
'a'+'via'+'n'='AVIAN'
(Other definitions for avian that I've seen before include "Like rails, for example" , "To do with birds - like a dangerous flu" , "Pertaining to or characteristic of birds" , "Resembling a bird" , "Birdlike" .)