Mistakenly sent home (4)
I believe the answer is:
nest
'home' is the definition.
(a bird's home)
'mistakenly sent' is the wordplay.
'mistakenly' indicates an anagram.
'sent' with letters rearranged gives 'NEST'.
(Other definitions for nest that I've seen before include "Rook's residence?" , "Accommodation for hobby, say" , "comfortable residence" , "Shelter in which to lay eggs" , "In which to lay eggs or give birth" .)