Bird held by older nephew (4)
I believe the answer is:
erne
'bird' is the definition.
(erne is a type of bird)
'held by older nephew' is the wordplay.
'held by' indicates the answer is hidden within the clue.
'ERNE' is hidden in the letters of 'older nephew'.
(Other definitions for erne that I've seen before include "Irish lough" , "Sea-eagle in an Irish lake" , "Great lake in Fermanagh with lots of islands" , "Flier" , "Irish river, loughs; sea bird" .)