"Mink" was my first thought based upon the size, shape, and spacing of the tracks. Another good way is to follow them and see where they do (and don't) go.

A mink is going to check out all the holes and nooks and crannies it can fit into, which can be quite small. Other clues along the way help to tell the story also.

Following a set of tracks of any animal right after a fresh snow is quite an education!

I love to go look for deer beds right after the fresh snow ends. They tell you exactly where and how the deer access the beds to evade us hunters. It gives some great insights into where I will be bow hunting next year.