Nice stuff, very sharp!
At first I thought the "snake on the log" was a Cottonmouth because the coloration looked right, but its body is not nearly stout enough and the head not triangular enough. I shot this one pointing down in a culvert with the 180mm f/2.8. They are very
ornery snakes, no doubt where the saying "mean as a snake" comes from.
It is most likely a painted water snake which are often mistaken for a cottonmouth. They are nonvenomous but still pretty aggressive. Both are all over the place around here
http://farm4.staticflickr.com/3233/2892562839_23e1c2c7f7_z.jpg