Bigotes
(UPDATE: When I returned to Mexico I learned that Mr. Bigotes had passed on to that great mouse house in the sky. Hopefully he was comfortable in the short time he ran around my shelf.)
I've done it again, accepted to care for another little clone mouse from Shadai's school's lab. He is different from the other tiny mouse we had. Colita was the extra clone that wasn't used in research, so she had no fear of man or mama and had a passion to investigate us and climb everywhere. No so with Señor Bigotes (Mr. Whiskers).
In most experiments there are two groups of subjects, one that receives the real thing, whatever that may be, and the other group that gets injected with water. Mr. Bigotes belongs to the later group and thus he is extremely wary of everyone, but especially of men. He is afraid and wary of everyone, but he won't go near a man.
At any rate, we have a "floating" shelf that is ideal for a mouse run and I have provided lots of climbing equipment like tiny picture frames and ceramic figures. But Bigotes is so fearful that I hit upon putting the birdhouse made of clay on the shelf to see his reaction.
For a day he walked around the perimeter of the tiny house, daring only to peek inside the windows to see if it was safe. But the next day he ventured inside and began to peek OUT of the windows, checking to make sure, I think, that he was actually inside and nothing had happened to him.
From then on it has been his favorite place in the universe. He sits contentedly in the doorway watching the world go by him when he isn't napping or coming out for a bit of lettuce or a cashew or running to his little doll tea cup for a drink of water.