I have only seen three western diamondback rattlesnakes and all three were at Organ Pipe Cactus National Monument in Southern Arizona. They are not found in the area near Redlands, but they are found further east in Southern California.
The first two I saw were in April 1998 while I was with Sam and Andrew. We were starting out from Alamo Campground to do a backpacking trip, hiking up through Grass Canyon, over the ridge of the Ajo Range, then down through Alamo Canyon and back to the campground. We were only a short distance from the campground when a western diamondback, about 20 feet away, started rattling at us from beneath a palo verde tree.
If it had not started to rattle, we'd have never seen it. It was pretty intimidating, upper body raised in the air in an aggressive manner, rattling constantly. I've never been particularly afraid of rattlenakes, but this one caught my attention and I was very careful getting anywhere near it. I would not have been surprised if it had come toward me.
I wanted to get a better picture of it, so I used a stick to coax it out from under the palo verde tree. There, it did not seem as aggressive or threatening.
The second western diamondback we saw on that trip was the next day, after we had crossed over the ridge and were following a mostly dry streambed down the backside. A very large snake, apparently oblivious to us, slithered along the other side of the stream, at this point with some water in it, then carefully tested the water, fully stretched out and exposed. It did not rattle or coil, a complete contrast to the snake the day before. This snake was just pure pleasure to watch, like watching an animal documentary.
We just sat and watched it for quite a while. It eventually swam a short distance across the stream.
Partially in and out of the water.
The third western diamondback I've seen was in March 2008, also on a hike with the young men, taking the same route through Grass Canyon, over the ridge and back down through Alamo Canyon. This time we were further out from Alamo Campground when we saw the snake, but not as far as Grass Canyon. I was leading and walked right by the bush the snake was under. It started to rattle after a couple of us had already passed. I coaxed it out from under the bush, with one of my hiking poles, for a better picture.
Updated: March 22, 2010
Judy and I just returned from a trip to Organ Pipe Cactus National Monument. While hiking out of Alamo Canyon toward the campground, along the trail past the old brick structure, Judy encountered a western diamondback rattlesnake about ten feet off the trail, rattling at her. This is the fourth western diamondback I've seen, all in Organ Pipe. Like the first one I saw, this one was feisty. He rattled continuously and loudly, almost constantly in strike mode. Below are several photographs of the snake.