Thanks Steve.
Here's a test render with particles. Add the moon and setup the bat wings so I can randomize the start of the wing flap, so they don't flap in unison (pose slider adjusts the lag of an orient like constraint on the geometry bones to an expression bone).
I'm getting render artifacts from the streak emitter. Most likely because of multiple copies of the same model. I may try sprites instead of streaks, will probably render faster too. I might add an expression to the rate of emissions on the particle emitter, so it's not a constant flow of flames. The bat model still needs work on the rigging. I want to set it up so I can set the bats on pathes in the chor, right now the model bones are animated, unneeded key frames. Still lots to do, but getting close.
bats.mov