Insects and other foods the trout may be eating:
1.   Blue-winged Olives
2.   Little Black Winter Stoneflies
3.   Streamers - matching sculpin, baitfish and small crayfish
4.   Midges

Basics of Fly Fishing - Trout Food Series - Mayflies - Part 3
If you read yesterday's article, I'm sure you noticed that I elaborated on the fact that
trout could see a nymph under the water much better than a fly (dun) on the
surface. I went into detail as to why this is a fact. Even so, few anglers really pay
much attention to what it is they are trying to imitate with their nymph. They select
and tie flies with great care to imitate mayfly duns but assume just about any hook
with hair on it will work for mayfly nymphs. They go more by what they see and think
of the nymph than what it actually resembles. One reason is that the word "nymph"
is a catch all word in the fly fishing world. It is used more for the name of a trout fly
than a stage of an insect's life.
Today's article continues

Copyright 2009 James Marsh