Poet's starting yearly excursion around the Shetlands (5)
I believe the answer is:
yeats
'poet's' is the definition.
(Yeats is an example)
'starting yearly excursion around the shetlands' is the wordplay.
'starting' says to take the initial letters.
The initial letters of 'yearly excursion around the shetlands' is 'YEATS'.
(Other definitions for yeats that I've seen before include "Irish poet (The Winding Stair)" , "Poet William Butler or painter Jack B" , "Irish poet, 1923 Nobel Prize winner" , "W. B. -- , Irish poet/dramatist" , "Irish poet and dramatist, d. 1939" .)