Eastern milk snake Lampropeltis triangulum triangulum
It seems calculated to infuriate me, that on the day before a holiday about a mythical purging of snakes (a symbol for the forced conversion of pagans to Christianity), I should find a dead snake in my yard, killed by a predator that couldn't be bothered to eat it. Eastern milk snakes are purportedly quite common in our area, and yet I've personally only encountered one live one, and this dead one. I took care of a couple captive specimens at Drumlin Farm, fairly calm educational animals that eventually died of gout.
Eastern milk snakes are constrictor snakes that prey on mice and other small animals, including other snakes. Sometimes their orange and brown pattern causes the over-cautious to mistake them for copperheads--a venomous species (which enjoys protected status, so don't go chopping them up with your shovel you big bully). Milk snakes are so-called because they were frequently noticed in dairy barns. Hopefully no one actually believed the ludicrous idea they were feeding on milk, since it should be clear that they were feeding on mice in the barns.