mulch attracts mice, voles. It keeps them cool in the summer and warm in the winter. I don't use any mulch with my potatoes, they did really well this year.

The plants have died back now, is that the time you pick them out of the ground?

I've heard of people doing potatoes in containers, makes "hilling" and harvest real easy.

There seems to be a persistant myth that mulches made of vegetative materials will attract voles and other vermine. There is no evidence that thpse wee critters are more active in mulched versus unmulched gardens. if there is food available they will move in there whether any mulches are present or not. Since these wee buggers want to eat some of us have found that cages around the plants they like to eat, made from 1/4 or 1/2 inch mesh hardware cloth, is effective.
This link may help dispell some of the myths.

Here is a link that might be useful: Mulches and rodents