There are birds that fly directly across the Pacific from Southeast Asia to our western states like California, Oregon and Washington.
We also worry that birds will stop off in some of the U.S. territories in the Pacific like Guam, and Hawaii.
We have chosen sites and species of birds that we think are the most likely ones that contact birds over in the Russian Siberian side that have the potential to migrate and make contact with birds in North America.
The United States is a huge country. There are millions of birds on the move -- but we're going to work smart.
Initially, wild birds are primarily victims. Someday they may become vectors. We don't know how that will play out. What I would like to see is the virus stopped before it gets to America so we don't see the last reel of this film played out in North America.
By the timing of the spread and the pattern of outbreaks within a country and between countries, it does not make sense relative to a role for migratory birds as a means of spreading the virus.