Pair hold strong affection for bird (6)
I believe the answer is:
plover
'bird' is the definition.
(plover is a kind of bird)
'pair hold strong affection' is the wordplay.
'pair' becomes 'pr'.
'hold' indicates putting letters inside.
'strong affection' becomes 'love' (I've seen this before).
'pr' placed around 'love' is 'PLOVER'.
'for' is the link.
(Other definitions for plover that I've seen before include "Shorebird with pointed wings" , "Shore bird with long pointed wings" , "Short-billed shore bird" , "Wader" , "Lapwing, for example" .)