Fig. 2
From: Wild bird surveillance for highly pathogenic avian influenza H5 in North America
Poultry sales in 2012 by state in relation to major waterfowl flyways in North America. Poultry sales (layers, pullets, broilers, turkeys) as an index of density can be used to stratify wild bird surveillance sampling during the non-breeding season. This approach would target sampling in locations where the greatest risk of economic damage could occur. Sampling at high latitudes during the breeding season when populations from the various flyways (including Asian flyways) overlap can identify the potential for spread among the flyways. Poultry data from the 2012 Census of Agriculture [13]