Figure 3. Host migratory distribution and IAV circulation in the North Atlantic. Significant discrete phylogeographic transitions between Iceland, the rest of Europe, and North America are represented by arrows from mainland Europe to Iceland (Bayes Factor (BF)= 110,622), Northeastern USA to Iceland (BF= 414.87), and Iceland to northeastern Canada and Greenland (BF= 127.22). Arrows signify directionality and greater arrow width corresponds to higher BF support of phylogeographic transitions between intracontinental geographic states. BFs for state transitions between all global regions can be found in Supplementary Table 4. Host migratory ranges for populations of shorebirds (yellow), gulls (green), ducks (blue), and geese (red) were compiled from individual species-specific shape files acquired from IUCN Red List (IUCN, 2021). Species-specific migratory range maps can be found in the Supplementary figure 7.