Thanks, J. If it was bat related I was a little nervous about just tearing the tar paper off to see what was what.
Hmmm, more description... well I said they were rabbit pellet size. Around here rabbit pellets are about 3/8" long and about 1/8" thick. These things are all stacked like they've been pooped out of something that is nested above them. I'm no bird expert, but do starlings and swallows nest between paper and wood like is the case? They don't build regular nests ?, or are their nests hidden like these would be? Also, this just occured sometime between fall and now. Don't these birds migrate?
I don't see any girdled trees and have never seen a porky around here, but won't rule it out, though it would have to be an awfully thin one to fit in this space (about 3" out from the wood).
They could even look like some kind of dead larvae, but even magots crawl off when their living quarters becomes undesirable.
I guess maybe my best bet would be to put on the Carharts, gloves, find a scarf to cover my neck, put on a full face helmet and start ripping the tar paper off. Might be interesting /forums/images/graemlins/shocked.gif