66 cm (26") Fairly common. Summers on Arctic lakes, winters along Pacific coast.
Summer: light gray crown and nape; iridescent purple, green or black throat patch; black-and-white checkered back.
Winter: the crown and nape are paler than back unlike Common Loon and there is sharp contrast between light and dark areas of neck; gray cap extends to include eye; often thin dark line under chin.
Song: harsh "kwow", rising wail.