If it sees any movement inside the house, it takes off, so when I know it's around (usually dawn or dusk), I sit in the dark with the camera hoping to get a picture.

I can't say if this is a male or female. It does seem smaller than the other fox, and they seem to share the yard as a repository for dog biscuits. Foxes are territorial, so maybe this fox being around explains why my friendlier fox only visits once a week lately.
Last night while I was waiting for it to come back, I noticed a half-grown mouse scrounging around in the grass just outside the dining room window. I'm sure it will end up in my house one of these days.