Bird flew low (3)
I believe the answer is:
owl
'bird' is the definition.
(owl is a kind of bird)
'flew low' is the wordplay.
'flew' is an anagram indicator (I've seen 'flying' mean this (letters fly around into new positions)).
'low' with letters rearranged gives 'OWL'.
(Other definitions for owl that I've seen before include "Predator" , "Lear's loved a Pussy-cat" , "Creature" , "Someone solemn or wise or staying up at night" , "Night hunter" .)