It was completely unexpected of course since it was the middle of the day and the bat was on the ground. I had only seen bats in flight before so it was interesting to see one up close, but also concerning of course. I actually noticed it as I was walking over it, I stopped, took some pictures from behind, then walked over it again, saw it turn its head and look at me, then took one from the front.
I was worried it was sick, but it moved its head, so hopefully it wasn't too sick. I mentioned it to my dad and he told me about white nose syndrome, which is a mysterious disease killing Massachusetts bats. The name comes from the white fungus growing on the bats' noses. I didn't see any on this bat's nose so hopefully it's in the clear.
For more information on white nose syndrome:
Boston.com article: http://www.boston.com/news/local/articles/2008/02/21/bat_sickness_reaches_mines_in_western_massachusetts/
U.S. Fish and Wildlife: http://www.fws.gov/northeast/white_nose.html