Lesson #1: Remember that some moths fly on chilly nights! It was cool (47°F) and foggy, and I wasn't thinking there would be any moths to see, but I left a light on by accident, and when I went to shut it off, these two moth species were nearby.
Lesson #2: Don't assume a distinctive color will make an identification easy. When I saw this pale green moth with lines running across the wings, I was excited — not only because it was pretty, but because there aren't that many green moths with stripes, so I thought identifying it would be relatively straightforward.
Well, I turned to the plate in the book showing green moths with dark lines, and wouldn't you know, they didn't look quite right. I didn't know what else to do, so I decided to look at some images of those species on the Internet (e.g., Chlorosea, Nemoria, Dichorda, Synchlora) to see if perhaps they would look different online. Sadly, they didn't. But luckily, another moth appeared in my image search that looked like a better match.
This moth wasn't green, but the wing shape and the wing markings were very close. It's not a perfect match, but I've read that there are 10 species of Eusarca on the West Coast, so for now I'll just call this Eusarca sp.
Lesson #3: Remember to look at what's right in front of you! This is the second species of moth I encountered on 23 October (below). At first I couldn't find it in the book. I looked and looked, and looked and looked. I couldn't believe I wasn't able to find it because it's a relatively large moth with fairly distinctive colors and patterns.
Eventually I had to give up looking in the Moths of Western North America and check a smaller book. There I came across a moth that had potential — Sabulodes aegrotata, sometimes called an Omnivorous Looper. I went back to the Moths of Western North America and found this species on the same page as the green moths I had been looking at! I had bypassed that page because I had started there with the green moths, and figured this ginger-colored moth with the vanilla-bean spots had to be on a different page. Not!
Here are two close-ups of Sabulodes aegrotata. It sounds like this is a common moth, but I just haven't noticed it myself yet. Perhaps you'll see it in a nearby yard!