The timing and direction of this virus’sdissemination, which coincided with waterfowl migra-tion patterns, together with phylogenetic and geospatialdata (3,4) support the hypothesis that Gs/GD H5N8 clade2.3.4.4 was introduced into North America through theBeringian Crucible via intercontinental movement ofmigratory waterfowl (5,6).