L 18" ws 43" wt 15oz (420 g)
Slender with long wings and tail; wings raised in dihedral.
Wingbeats smooth, rowing; long wings and tail; slender body.
Voice: Two call types. Piercing, insistent whistle eeeya or high, very thin sseeeew given mainly by female and young. Dry clucking or barking series chef chef chef . . . to rapid staccato kekekekeke . . . given mainly by male.