This yellow-eyed, black-beaked white bird is easily recognizable. It is 52–71 cm (20–28 in) long, with a 125–150 cm (49–59 in) wingspan. Also, these owls can weigh anywhere from 1.6 to 3 kg (3.5 to 6.6 lb). It is one of the largest species of owl and, in North America, is on average the heaviest owl species. The adult male is virtually pure white, but females and young birds have some dark scalloping; the young are heavily barred, and dark spotting may even predominate. Its thick plumage, heavily feathered taloned feet, and colouration render the snowy owl well-adapted for life north of theArctic Circle.
Snowy owl calls are varied, but the alarm call is a barking, almost quacking krek-krek; the female also has a softer mewling pyee-pyeeor prek-prek. The song is a deep repeated gahw. They may also clap their beak in response to threats or annoyances. While called clapping, it is believed this sound may actually be a clicking of the tongue, not the beak.
(From Wikipedia, March 2015)