What percentage of wild birds have it? I couldn't find an answer to that question.
Great job. I did find a tupo:
"You can's stop it from spreading. It's even in wild bird dander."
That wild bird dander thing is kinda scary!!!! I'm surprised my flock hasn't gotten it given all the house sparrows, grackles, etc that are around 24x7x365. And then there are the other migrating birds that hang out all summer.