Alfred Newton, 1911 Encyclopædia Britannica (1911)
“ Common to the most northerly forest-tracts of both continents (for, though a slight difference of coloration is observable between American examples and those from the Old World, it is impossible to consider it specific) is the much larger S. cinerea or S. lapponica, whose iron-grey plumage, delicately mottled with dark brown, and the concentric circles of its facial disks make it one of the most remarkable of the group. Then may be noticed the genus Bubo—containing several species which from their size are usually known as eagle-owls. ”
