Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
After camping atop the Gravelly Range and mostly dodging thunderstorms throughout the day, we set up to camp in the evening at Cottonwood Campground along the upper Ruby and drove to fish a nearby reach that looked good on Google Earth. There wasn't much visible bug activity and I didn't see a single fish, but I did manage to find five small to medium rainbows on nymphs and soft-hackles.