This fall and continuing into early winter, one of my go to patterns have been Beatis imitations commonly known as Blue Wing Olives. These patterns have been producing far longer into the year than normal. Typically this time of year the only insects we are likely to see are midges. With all this mild weather I am continuing to see regular Baetis activity, particulary on overcast days.
Although there has been some surface activity, most of my fish have been coming below the film fishing nymph and emerger patterns. I'm sure all this will finally come to an end with the cooler temperatures in the forecast, but it was good while it lasted.
I'll leave you with an example of one of the Beatis nymph patterns that produced very well in recent weeks. I discovered the pattern years ago while fishing the San Juan River in New Mexico. I liberated it from the jaw of a large rainbow trout, took it home, duplicated it on my vise and have been using it ever since.
Baetis/Blue Winged Olive Nymph
Hook: TMC300R size 18-24
Tail: 3 Pheasant tail fibers tied short (hook gap in length.
Body: 16/0 Olive Thread
Shellback: Pheasant tail fibers from tail
Rib: Olive thread
Thorax: Black antron fibers
Legs: Fibers from thorax spit and tied to the sides