Insects and other foods the trout may be eating:
1.   Blue-winged Olives - mostly Little BWO - Isolated hatches
2.   Mahogany Duns
3.   Midges - hatching in isolated locations
4.   Little Yellow Stoneflies - hatching (Little Summer Stones)
5.   Slate Drakes - hatching
6.   Cream Cahills - hatching in Isolated locations
7.   Beetles
8.   Grasshoppers
9.   Ants
10. Inch Worms
11. Crane Flies
12. Helligramite
13. Streamers - matching sculpin, baitfish and small crawfish

Little Yellow Quills
The Little Yellow Quill mayflies are a little known but very common mayfly in the
streams of Great Smoky Mountains National Park. You will rarely even hear anyone
mention them. My explanation for that is that the Little Yellow Quills appear at first
glance to be a Light Cahill that hatches earlier in the year. When we started
studying the insects in the park, collecting specimen and making macro videos of
them, we discovered the yellow mayflies were not Light Cahills. They were clingers
and that was about the only similarity in them and the Cahills.

There is a group of mayflies from different genera within the Heptageniidae
family that are now lumped together under the title "
Heptagenia Group". The three
genera included in the group,
Heptagenia, Nixe and Leucrocuta, are very
closely related.

This common two-tailed, yellow mayfly that starts to appear in late summer in the
Great Smoky Mountains National Park that I was not able to positively identify at the
time is one of the
Leucrocuta species. These mayflies are common in the
Mid-Atlantic, Northeastern and New England states. I think theres probably more
than one species of them. We still have not taken the time to try to determine the
species under a microscope from keys.

The clinger nymphs of these mayflies are very common in the smaller brook trout
streams in the higher elevations. You can find the duns and spinners in very
plentiful quantities at times. If you consider the number of them on the water on a
square yard basis, they would compare to the Quill Gordons or other larger hatches
in the Smokies. They also occur in the lower elevation streams but they don't seem
to be quite as plentiful as they are in the streams at higher elevations.

One reason I am convinced there is more than one species is the fact you will find
them for several months starting in late summer ( we show the 3rd week of
August) and continuing as late as the first week of December depending on the
weather. Also, there seems to be some minor differences in the ones I have
closely examined. I don't think any of the differences I have noticed has anything
to do with their behavior and certainly are not different enough to require different
imitations or flies. Most anglers I have asked thought these mayflies were "Light
Cahills" but they are not
Stenacron or Stenonema species.

These are the species officially listed for the park but I would be willing to bet that
there are more of them.
Heptagenia julia
Heptagenia marginalis
Leucrocuta thetis
The "Little Yellow Quill" is the common name given to several species of the
Leucrocuta genus of mayflies that are fairly common in many Eastern streams.
One thing for sure is that the name "Little Yellow Quill" certainly fits the ones in
the park. By the way, they shouldn't be confused with the Western "Yellow Quill" or
Epeorus Albertae.

                                             Little Yellow Quill Dun

Copyright 2009 James Marsh