Sheathbill

The sheathbills are a family of birds, Chionididae. Classified in the wader order Charadriiformes, the family contains one genus, Chionis, with only two species. They breed on subantarctic islands and the Antarctic Peninsula, and the snowy sheathbill migrates to the Falkland Islands and coastal southern South America in the southern winter; they are the only bird family endemic as breeders to the Antarctic region. They are also the only Antarctic birds without webbed feet.

Description

They have white plumage including a thick layer of down, with only the face and leg colours distinguishing the two species. They look plump and dove-like, but are believed to be similar to the ancestors of the modern gulls and terns. There is a rudimentary spur on the "wrist" (carpal) joint, as in plovers. The skin around the eye is bare, as is the skin above the bill, which has carbuncular swellings. They derive their English name from the horny sheath which partially covers the upper mandible of their stout bills. They are commonly known in the Antarctic as "Mutts" because of their call which is a soft "Mutt, mutt, mutt"