Bird in a gaggle (5)
I believe the answer is:
goose
'bird in a gaggle' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for goose that I've seen before include "Supposedly foolish bird" , "Large water bird" , "Large waterbird" , "Marches in an odd fashion" , "Gander's mate" .)