Hear cuckoo and another bird (4)
I believe the answer is:
rhea
'bird' is the definition.
(rhea is a kind of bird)
'hear cuckoo' is the wordplay.
'cuckoo' is an anagram indicator.
'hear' is an anagram of 'RHEA'.
'and another' is the link.
(Other definitions for rhea that I've seen before include "New World flightless bird" , "Ostrich-like bird - satellite of Saturn" , "Moon" , "Titaness" , "Greek goddess of fertility - running bird" .)