I looked up finches last night. It looks like my two visitors are Zebra Finches. Walter took some pictures of them this morning. I will print the pictures and take them to one of the professors I work for. He is an ornithologist; he can confirm identification. One of the perks of working for an ornithologist is that I can legally search for tits on Google during work hours.

I will post pictures later.

I still think the finches are a pair that escaped from a home or breeder. They appear to be thriving.