Low-flying bird (3)
I believe the answer is:
owl
'bird' is the definition.
(owl is a kind of bird)
'low-flying' is the wordplay.
'flying' indicates an anagram (letters fly around into new positions).
'low' is an anagram of 'OWL'.
(Other definitions for owl that I've seen before include "Bird of prey with front-facing eyes" , "Solemn person" , "Bird of the 18" , "Predator" , "Harry Potter's Hedwig, for instance" .)