Thank you so much for the ID. After doing a little research on this site and others, Pacific Spiketail looks like a great match. Here is a ventral view for comparison to my image. (Courtesy of CA Dragonflies & Damselflies).

Wow! That is one good-looking dragonfly and now I really wish I had managed to get a top-side image. To read others comments it sounds as though they are very difficult to approach and rarely land long enough to be photographed. In my case, I think the only reason I managed to get this shot is because it was very busy eating a rather large insect (possibly a robber fly or bee?) and also because I happened to be walking around with my 400mm lens. As soon as I attempted to approach more closely, it took off. Too bad it was hanging in such deep shade, or I might have managed a Guide-worthy image. Still, what a cool sighting!!

It's showing a different angle than the other (limited) pictures in the guide and also is the latest date on there.

and I'm very glad to hear that it is of some use! If I have time over the weekend I will see about putting a little more effort into the post-processing of the image to see if I can get it looking any nicer and then upload the improved version.

...of wading through all the species on her website when you posted this message. It's a good (and thorough!) site. I love the fact that there are range maps too.