Bird; boast (4)
I believe the answer is:
crow
I believe this is a double definition.
'bird' is the first definition.
(crow is a kind of bird)
'boast' is the second definition.
(to crow about something is to boast about it)
(Other definitions for crow that I've seen before include "One commonly stoned" , "Blow one's own trumpet" , "Boast gloatingly, American Indian" , "Black bird with raucous call" , "Bird - birdcall" .)