Nostril

External openings in the upper part of the bill which allow them to breathe without opening their mouth.

The nostrils (external nares [NAY-reez]) of some birds such as crows, ravens, and grouse are protected by or by bristles, which may serve these birds also as organs of touch. The nostrils of hawks and falcons are surrounded by a soft membrane (the cere). In pigeons and doves, each nostril is protected by a swollen opercula (sing. operculum), a cover of skin that only allows a little passage of air.