Objects mysteriously appearing: paranormal or rodents?

To preface this post, I am a complete non believer in the paranormal (and an atheist). What I'm really looking for is a logical explanation for whats happening in my house and/or people that have had similar experiences.

First of all, I live in an old "twin" house in NJ (twin meaning theres two houses physically attached). The house was built in 1920. I live here with my mother and we've had absolutely no other unusual experiences in this house other then what I'm about to mention.

The other day when my mom was putting up Christmas decorations she found on top of a cabinet in the kitchen a small plastic statue. She thought it was a statue of Jesus but it looks more like a shepherd or maybe an apostle like something from a nativity. Its completely white and has a hole in the bottom as if it was meant to be stuck on a small pole or something. We thought okay maybe a previous owner left it there. So we put it on the windowsill in the kitchen.

Two days later when my mom gets up she sees next to the statue a small silver cross on a chain that wasn't there before. It was sitting neatly on the windowsill next to the statue. Now she was extremely freaked out. I know our house has a mouse issue as I've found droppings in the basement. But its awfully strange that a cross that we've never seen before would suddenly appear next to a statue we never seen before.

So what do you think? Paranormal or a rodent with a penchant for shiny objects?