Gopher Snake, Pituophis catenifer
Also known as P. melanoleucus, P. ruthveni, and P. vertebralis.
Native to British Columbia to Indiana, and south through all of western North America to northern Baja California, and northern Mexico.
Diet is almost any small animal or bird it can find.
Pretty much harmless to us. Although sometimes they will pretend to be a rattlesnake. No rattles, no venom.