We actually saw it yesterday morning. At first we weren't sure what it was, just that something kept spooking our chickens and a few of them had disappeared. Several days ago, it screeched at me before running away, but I only caught a glimpse of it through the brush. I'd never heard a cougar before so I wasn't sure that was the sound they made, and I didn't get a clear enough view that time to be 100% sure - but I highly suspected it.
Then yesterday morning, we actually saw it. It apparently had gone after one of our chickens and gotten close enough to take out a bunch of feathers, but the chicken got away and we heard the commotion.
I have to say, if it hadn't been in our backyard, it would've been pretty incredible to watch. It's not very often you get that close to a predatory cat in hunting mode.
As soon as the door opened so I could take a shot, it disappeared into the brush with lightning speed.
Anyway, all that is to say, we are certain it is a mountain lion. It seems to have determined that our backyard is an easy source of food, so I'm pretty sure it will come back.