It's been a while since I posted, but seeing John C. posting again made me think. I have to agree with him, I worked a couple of nights on the project he references and for the most part we drove only a couple of miles in a night. On rare occasion we had bats move 20+ miles during the night. I'd also trust his data about migration, as he's been on FAR more winter/summer surveys than I, or many of us.
However, I did want to say that just because bats don't move 250 miles all that often doesn't mean that bat predators don't move that far, and farther. It seems like this argument gets boiled down to bat or human transmission so often, when it really could be anything that transports bats or soil, or for all we know air down the alleghenies at approximately X rate per year.
Certainly it's possible that cavers do that, or cave rats, house cats, people transporting boats to the Okefenokee swamp, birds, bees. Fairly unlikely that it's wind... it just doesn't go that direction so much.
Unless... all the farting in the Schoharie cabin is to blame.