Gular skin

In ornithology, some bird species have gular skin, an area of featherless skin that joins the lower mandible of the bill to the bird's neck.

It is prominent, for example, in members of the order Pelecaniformes. In many species, the gular skin forms a flap, or gular pouch, which is generally used to store fish and other prey while hunting.

In the Cormorants, the gular skin is often coloured, contrasting with the otherwise plain black or black-and-white appearance of the bird. This presumably serves some function in social signalling, since the colours become more pronounced in breeding adults.

In Frigatebirds, the gular skin or sac is used dramatically. During courtship display, the male forces air into the sac, causing it to inflate over a period of 20 minutes into a startling huge red balloon.

Sac gulaire