Birds gathering for drink we hear (4)
I believe the answer is:
bevy
'birds gathering' is the definition.
'bevy' can be an answer for 'gathering' (bevy is a kind of gathering). I am not certain of the 'birds' bit.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for bevy that I've seen before include "Flock of birds, girls or other groups" , "Pack" , "Group of e.g. girls" , "Many women" , "Flock of larks; group of beautiful women" .)