|....................... .................... ...Fly Fishing Yellowstone National Park
New KISS Bug Series - Part 26
Pale Morning Dun
The Pale Morning Dun Spinners are eaten by trout like humans eat popcorn and peanuts. You will find
spinner falls on some days taking place both in the early mornings and during the late afternoons. On the
early season hatches during June on the Firehole and Madison Rivers, they usually fall from about 8:30
AM until around 11:00 AM and again from about 6:30PM until complete darkness which takes place as late
as 9:30 PM and even later. Generally, the spinner falls occur in the mornings during warmer weather. In the
later part of the Yellowstone season, the infrequens species females tend to fall only in the early mornings.
During the month of June, on the Firehole and Madison Rivers, the hatch occurs around noon. It can last
until the first week of July. Later, the day of the hatch, near late afternoon, they mate over the water and
the males fall dead at that point in time. Many fall on the water. This is what anglers are usually referring to
as the evening spinner fall. Sometimes, depending on the weather but for sure the next morning, the
females deposit their eggs by flying over the riffles and dipping slightly into the water. They then fall spent
Look for the spinners to fall over ripples upstream from the calmer water from which they emerged. Warm,
calm to light breeze days are the best for large spinner falls. The spinners can be very difficult to see
although the insects may cover the water. If you are not familiar with the spinner fall, it's possible to be on
the water and not even know it is taking place. The trout tend to sip the spinners and although you may
see the rises you may not have a clue as to what the fish are eating. They are very difficult to see even
when there are a lot of them on the water, especially during the low light conditions they occur under. A
skim net will quickly tell you if they are on the water and is the best wayto determine if the spinner fall is
occurring. I use one that stays in a small pack attached to my landing net. Even though I rarely use the
landing net, I keep it attached to my back when I want to check for spinners. You want to check areas
where the spinners congregate, such as slow water below riffles, seams of current and eddies.
We prefer the Perfect Fly spent wing imitations of the PMD spinner because it is by far the most realistic
imitation of the spinner available. You can use a dun imitation when they are falling. Usually, the females
actually touch the water to deposit their eggs but sometimes they drop them from slightly above the water.
The trout may take them while they are depositing the eggs but they are more likely to eat them after they
die and fall spent into the water. For that reason, we always go with the spent wing spinner imitation. The
females die as soon as they have deposited their eggs. It's much easier for the trout to position themselves
downstream from the areas they deposit their eggs to eat the spinners than it is to chase them around the
faster water where they deposit their eggs.
Use a very light tippet and make an upstream or downstream approach that best presents a drag free
presentation for the type water you are fishing. Generally, a down stream presentation is best for smooth,
calmer water and an upstream presentation is best for streams consisting mainly of pocket water.
In rough water, you will want to concentrate on the areas the spinners would congregate in, such as
eddies, the ends of riffles and runs, and the heads of pools. It's much easier for the trout to pick off the
helpless spinners where they are concentrated in the slower moving water than the faster water.
|Pale Morning Dun:
Availability to trout:
Type of water:
Duration of hatch period:
Ephemerella infrequens/ E. inermis
Moderate to slow - smooth and broken surface