What is it about fall?

I can't say I have a favorite season, but for the last few years I've appreciated fall more than in the past.  Something about the nesting instinct, I guess.  Fall seems like the time to burrow, to lay in provisions, to gather up fuel....Yesterday's fire inspired me to go out and collect kindling this morning, I felt a bit like a squirrel gathering nuts.  Is there a deep reptilian or mammalian part of our brain that makes us want to prepare for winter?  A drive to bolster ourselves for the coming cold?  It was not a particularly pleasant morning, weatherwise.  But it wasn't raining and I was comfortable with just a sweatshirt.  Walking through the woods, picking up sticks, I could imagine myself as some pioneer woman.  I remembered the Girl Scout term for low dead tree branches, "squaw wood."  People have collected wood for centuries, prepared for the winter, gathered and stored their food.  After picking up sticks, I successfully started the snow blower.