There are three species of rattlers here on the Plateau: Southern Pacific, Red Diamondback, and Speckled. The most common ones here on our property are the Southern Pacifics.
4/14/10 Southern Pacific Rattlesnake (Crotalus viridis helleri). This one was a baby, less than 12" long. He was in my herb garden and Gil managed to get it into a bucket with a grabber and we released him into the chaparral over the hill behind the property.
Southern Pacifics are generally dark in color, with gray, black, tan & olive blotches, which camouflage well with our native decomposed granite. And, yes - you don't want to eff with these guys cuz they are venomous, but they also have no desire to eff with you unless provoked. They do serve a very useful purpose in that they help to keep the rodent population in check.