Well, one week later and I had all but given up hope of having the family of Garters still living in my yard

But I just found a (I believe) a very fresh skin by the concrete stoop.
The shed was still very soft, fully intact and clearly from an adult.
If it's soft and very flexible, it must be fresh, right?

I had been working all day close to that area and even staged tools (chainsaw) on that stoop.
I didn't notice the shed then.
I wonder if this individual snake hasn't already moved back to the stoop.
Its gotta be cool there up against the foundation wall.

Either way, I'm so happy to still have Garter Yard-mates.