Noun
used in some classifications for the swans
Source: WordNetThe steamer ducks ( Tachyeres ), geese and swans ( Anserinae ), the solitaire ( Pezophaps ), sheathbills ( Chionis ), some guans ( Crax ) and stone curlews ( Burhinus ) use a bony knob on the alular metacarpal to punch and hammer opponents. Source: Internet