California Department of Fish and Wildlife

Wild Migratory Bird Patterns & Avian Influenza

  • One of the most widely held speculations of the movement of the virus to North America is through wild migratory birds, particularly waterfowl and shorebirds in the Pacific Flyway. The Pacific Flyway is a migratory corridor for birds.
  • The Pacific Flyway stretches along the Pacific Coast from Mexico north to Alaska and into Siberia, Russia. It is feasible that a high pathogenic H5N1-infected wild migratory bird in Asia may pass the virus to another wild migratory bird in Siberia or Alaska. The newly infected bird would eventually migrate south back into North America, and ultimately in California. Pacific Flyway, courtesy USFWS
    The Pacific Flyway
  • Evidence of wild migratory birds carrying the virus during their migrations exists elsewhere around the world, especially in Europe.
  • The scientific community now recognizes movement of the virus via migratory birds as a very real possibility. However, this risk from migratory birds is still less likely than the risk of the disease entering North America from the legal or illegal importation of an infected domestic bird, or an infected traveler or his/her belongings.