I forgot to add Idaho to the list of states that have had cases of highly pathogenic avian influenza. Here's that article:
http://www.capitalpress.com/Idaho/20150120/highly-pathogenic-bird-flu-strikes-idaho-for-first-time
And here's an article about the third case being reported in Washington State, the first state in the US to experience cases of this strain of avian influenza:
http://nwpr.org/post/new-case-avian-flu-confirmed-washington-state
So far, these North American cases are not dangerous to humans, but highly contagious to other birds. Transmission is thought to be through wild waterfowl. Affected domestic birds have included backyard chickens, geese, wild waterfowl, and falcons.
There is a lot of info about this online, and fortunately this is not a strain that makes people sick, but it sure as heck is extremely bad for birds!
The "funny" thing is that now China won't allow import of our chicken (for processing and returning back to us, mostly). China is a country where the avian flu strain that sickens and kills people has been problematic for several years, resulting in many huge flocks being destroyed plus continued monitoring.
It's hard to stop migratory water birds. How many can cross the Rockies? I don't know. I'm only really familiar with the midwestern flyway region, which of course is mostly flat as a pancake. We are dealing with a lot of unknowns.