Walnut Season

Landscape boulder or squirrel work station?

I've been hearing this sound in my yard and my parent's yard.  It goes "screech screech screech" and sounds like rocks rubbed on a grater.  It's not a pretty sound.  It's the sound of squrrel teeth breaking into walnut shells.  Now I've tried to open walnut shells.  Each shell takes at least 5 blows from a hammer.  They are not easy to open.  So I have to admire the squirrel's ability.  Just imagine how strong those squirrel teeth are.  If the squirrels couldn't wear down their teeth with walnuts, they would probably be saber-toothed squirrels.  The squirrels use my landscape boulder as a work station.  The top of the rock is littered with walnut husks and shells.  They also use my front cement sidewalk.  I try to keep the husks swept away because they stain the cement.  But it's an impossible task because squirrels open new walnuts every day.  I guess it's just "walnut season."  It will pass just like the holiday season, Girl Scout cookie season, and rhubarb season.