What Maine Creature is Digging These Holes in My Lawn?

With all the melting of snow that we have had in the past few weeks that brought Maine one of the least amounts of snowfall during the meteorological winter, my lawn is bare once more. With the snow gone, I noticed that something was hiding beneath that snow.

Four mounds of dirt were on my front lawn, with two of them flanking a mound with a hole at the center that looked like it went down quite a way.

I had no idea what animal was responsible for this construction, or rather, the destruction of my lawn, but it did a lot of work to tunnel that hole out.

Two days later, more mounds appeared, but smaller in size and without holes.

This led me to believe that whatever was digging in my front yard had been doing this recently, and maybe these weren’t hiding under the snow. They may be fresh digs that this busy excavator piled up, as it likely created a network of tunnels under my lawn.

I knew nothing about what animal this could be, but it couldn't be that big based on the size of that hole, can it? What do you think did all this digging? Should I be concerned? Could this be a problem for my lawn? If so how big of a problem are we talking about? 

I think it’s time I turn my Nest cam toward this section of the lawn to see what I can see.