Okay, i was up until 3am watching the baby monitor. i did see something, but it wasn't what is leaving the marks, as there were no marks this morning.
At about 10pm, after i put the ducks to bed and turned the patio lights down, we saw a reflective eyeball on the monitor - just one eye. It was moving fairly quickly back and forth, and for a long time i thought it was outside the pen. My husband threw in the towel and went to bed around 11pm, but i kept watching the monitor, pondering what on earth could be out there that has just one eye.
After a while i realized that this reflective eye was inside the pen (the baby monitor has such poor resolution). And then eventually it's head turned and i could see that it did have two eyes, just one was not very reflective. And then i made out the form of a mouse or rat. Hard to judge size, but when my little bantams are walking past the camera they look like dinosaurs, so it was probably a mouse.
Anyhow, it spent several hours running back and forth at the perimeter of the pen. It never went under the blanket surrounding the aviary, where the rat trap was set. Oh well.
So the mystery continues. i guess it still may be a snake, and perhaps the snake is after the mouse (meeces) that hangs out in this pen? i generally don't see the tracks two days in a row, they usually skip a day or two. That might support the theory of the snake, as it wouldn't need to eat a mouse every day.
Hurry up with that game cam,
Walmart! i'm exhausted!