Bird shown by leaders in British-Irish society (4)
I believe the answer is:
ibis
'bird' is the definition.
(ibis is a kind of bird)
'leaders in british-irish society' is the wordplay.
'leaders' indicates taking the first letters.
The first letters of 'in british irish society' is 'IBIS'.
'shown by' acts as a link.
(Other definitions for ibis that I've seen before include "Type of bird" , "Wading bird of tropical waters" , "One has large bill" , "Hotel group" , "State of central US, capital Lincoln" .)