Looks like the same ones we have in Central Wisconsin where I grew up. We called them pine snakes or fox snakes but not sure on the formal name. They will curl up like a rattle snake, wiggle their tail & strike at you just like a rattler but are harmless. May be a different species but without seeing it in action I'm not sure. I wish you wouldn't kill them as they are very beneficial for mouse control. Just catch them and take them further into the country.

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