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 .
|This article is part of Project Glossary, a All Birds project that aims to write comprehensive articles on each term related to animals.|
|This article is part of Project Anatomy, a All Birds project that aims to write comprehensive articles on each anatomical term related to birds.|