"Flavs" - Small Western Green Drakes
.............................Fly Fishing Yellowstone National Park

Flavs (Small Western Green Drakes) - (Drunella sp) - Nymphs and Emergers
The "Flav" nymphs are crawlers that prefer moderate to fast currents. They do not live
in still or slow moving water. Like many crawler nymphs, they move out of the faster
water of the runs and riffles to nearby slower water to hatch. This may be calm pockets
in heavy pocket water or the slow side of current seams in smoother water. Trout feed
on them with ease during their movement to the slower water to hatch and that is the
easiest time to catch them on an imitation of the nymph. They emerge in the surface
skim and they are very subject to being eaten as they attempt to get to the surface to

A few days prior to the hatch and in the mornings during the hatch prior to their
emergence, you can use the standard up and across presentation using a strike
indicator. Fish the nymph near the bottom on the slow sides of the current seams, in
calmer pockets behind boulders and in the slower water along the banks in fast moving
pocket water. You will need to weight it fairly heavily using non-toxic weight.

These mayflies emerge for only an hour or so during clear, bright days. Like many
mayflies, the hatch tends to last much longer if it is a cloudy or overcast day. Normally
the hatch occurs in the afternoons. The nymphs split their shucks in the surface skim to
emerge into duns.

During the time the nymphs are attempting to get to the surface to emerge after the
hatch has started you may want to try an emerger pattern. You can use an up and
across presentation in the pocket water streams allowing the fly to swing from the
bottom to the surface. In smooth streams you may use a down and across presentation
again, allowing the fly to swing to the surface. Although the trout will take emerger
imitations very well, most anglers prefer to fish a dun pattern.

Coming Up Next:
Flavs - (Drunella flavilinea) - Duns and Spinners

Copyright 2008 James