This is a mayfly adult. Mayflies are active in trout streams for most of the year, and in trout lakes during summer months when the ice is off. In fact, mayflies are probably second only to midges in the amount of insect activity that takes place during the course of the year.

While mayflies may emerge during winter months on tail waters, they really begin in earnest sometime during late February and into March, and continue throughout the late Winter, all of Spring, Summer and Fall, and into early Winter. From late November until late February, we are from an angling and match-the-hatch perspective, more or less, out of the mayfly business. Midges rule.

When days are short, dark and cold, the mayflies that are active are small and dark. A size #18 would be on the large size. As days get longer and brighter, bugs become larger and lighter in color. Green Drakes found in the Rockies are upwards of a size #10, for example.

Mayfly's lifecycle: Fertile mayfly eggs are laid by females. The eggs sink to the bottom of the lake or stream where they incubate for a certain amount of time. When the time is right, they hatch into baby bugs. There are millions of them. Alright, I haven't counted, but we'll assume there are at least millions, if that's okay with you. The little insects grow. They feed on plankton and other stuff that little bugs like to eat, and hide among rocks, or dig in mud or silt. (This picture is of a clinger/crawler, which lives in fast water.)

Certain mayfly types live in certain water types. The faster the water is the more oxygen there is. Bugs that live in faster water are generally less efficient in how they assimilate oxygen, and that's why they live there. These mayflies are built like body builders, and cling and crawl along rocks near fast water. The bugs that live in the slowest water often burrow into silt and mud, and are called burrowers. They are long and slender so they can slip into their little holes. They have dominant gills and effectively assimilate available oxygen.

Mayfly nymphs - or larvae, as they are usually called in the scientific world; I think nymph is a fly fishing term, but I'm not sure of that - live the majority of their lives in the water, assimilating oxygen through their gills. During this time, the insect goes through several instars, shedding their nymphal shuck, or exoskeleton, on the outside to accommodate the growth they are experiencing on the inside. All insects have exoskeletons. And, six legs.

During the last 24 - or fewer - hours of the bug's life lots of interesting things happen. Their wings, which are captured beneath their exoskeletons and have been maturing and getting very black (see the red nymph as an example), want to pop. The exoskeleton of the bug fills with gas and the bug floats - or swims - to the surface of the water. The gas forces the exoskeleton to split and the adult mayfly climbs out, then floats along the surface. The wings dry, the mayfly flies off and molts, and then returns as a mature adult to the water in order to mate, lay eggs and die. The spinners float along on the surface of the water. One cycle ends and another begins.

Trout eat all stages of the insect.

This covers the basics. There's lots more to it. I'll write more as time allows, and an interest is shown for more detail. Fair enough?

Mayfly Identification: How do you figure out what is what, anyway? It's a fine question, and one that will help all anglers understand what trout are feeding on and what flies will best imitate them.

Mayfly nymphs: have two or three tails. If an aquatic nymph has three tails, it is a mayfly. That's the first thing I check. If the bug has two tails, it may be a mayfly, but it could also be a stonefly, which we'll discuss later. The drop dead method of identifying a mayfly is to find the gills. When a bug's gills are on the abdomen - which is the back half of the bug - it is a mayfly.

 Mayfly emergers: most mayflies emerge at the surface, but there are exceptions. Isn't that the way it is in life? Interesting. Their exoskeleton splits from behind the eyes to the middle of the abdomen, and the bug begins to climb out. When it is hot and dry, the bugs get out and fly off quickly; when overcast, and/or cool and wet, they get out more slowly and drift on the water longer. This gives fish more time to check them out and decide what they will eat.

Mayfly adults: float along on the surface of the water and look like little sailboats in such a regatta. The lovely wings are upright and visible to the angler. The abdomen is slim and segmented and usually lighter on the underside than on top. The thorax is boxy and full with the wings and legs protruding from within. The wings are usually opaque and the veins are very apparent.

Mayfly spinners: are how we refer to the mature, mating and egg laying stage of a mayfly adult. The spinner's wings are shiny and clear; the color is gone. The body of a spinner is usually darker and the segments are more well-defined. This occurs as the bug dehydrates from a lack of food and water. Adult mayflies do not have mouths to eat or drink. They are there to mate, lay their eggs and either feed trout or birds, or fertilize the river as their carcasses - such as they are - rot. When spinners float along on the surface, the body and wings of the bug are usually flush with the water, and very difficult for the angler to see. Since most spinner falls occur during low light, the fish can actually see them very well, and will feed upon them voraciously. The picture at the left is of a callabeatis adult which has laid its wings flush on the water.

Mayfly patterns and how to fish them. I hope this helps you enjoy time on the water, and that it will help you better understand how the life cycle of an insect triggers trout feeding activity. We're going to fish from top to bottom, so hold on to your hat and enjoy the ride. Here we go.

Mayflies come in all types of sizes and colors. As a rule of thumb, remember that the shorter and darker the days are, the smaller and darker the adult insects will be; when days are longer and brighter mayfly adults are larger and lighter. When you tie or buy mayfly imitations, the flies that are under about a size #18 should be on the dark side; larger patterns on the lighter side. Again, there are exceptions. On the waters you fish, observe the bugs for yourself to determine the size and color of the bugs you see and will be fishing in the endeavor to fool wary trout. This is what we call fun.

The emergence though spinner stage can occur in anywhere from a few minutes to about twelve hours.

Fishing: trout feed on all stages of mayflies, except the eggs, which are very small. The challenge for the angler is determining which stage of the insect is the most active and available to feeding trout. That's going to be the stage that should be fished for angling success.

Nymphs: vary in size and shape. The key for the angler is imitating both as close as possible. When on the water, gently and carefully pick up rocks or seine the streambed to see what nymphs are mature and dominant. You will know which nymphs are ready to emerge by how dark the wing case is. The picture at the left shows the black wings ready to pop. In this case, the nymph is a crawler with a large, thick thorax and strong legs for clinging and crawling on rocks in fast water. The fly imitation would be tied with a full thorax, distinct ribbing on the abdomen and a dark wing case. Remember: the faster the water, the less time a trout has to examine a fly imitation; the slower the water, the more time they have to take a peek and decide whether or not to eat a natural or a fake. Tie or buy and fish flies accordingly.

This is a PMD nymph. Note that it is thinner than the crawler above, but the wing case is also quite black. It's not the best picture I've ever taken, but it shows the difference in shape, which is useful. This nymph would be found near slower water.

Basic nymph imitations include the hare's ear, pheasant tail, copper John, and biot nymphs. Recently, an old pattern has been reintroduced with a new name - the gilled nymph; this is also a fine imitation for a mayfly. All of these patterns can be tied thin or thick, with or without beads, and with or without weight. Each variation comes into play based on the depth and speed of the water being fished.

This is a pheasant tail nymph. The fly is easy to tie, works great and will imitate smaller, thinner mayfly nymphs very well. The pattern can also be tied fuller and in larger sizes.

The pheasant tail has become very popular through the years, and is actually one of the oldest nymph patterns we have. It was developed in England and referred to as Sawyer's Pheasant Tail. The original pattern was tied totally with pheasant tail fibers and copper wire. No thread; no peacock. The adaptation works well. If you are in to such things, try tying the original; test your skills, and see if you can do it. Tie the pheasant tail nymph.

This is a Hare's Ear nymph. It is a standard pattern for many anglers. The color can be varied by using different colors of dubbing material, and the thickness by how much material is put on the hook. Note the dark wing pad, the taper of the fly, and the clear segmentation of the abdomen. The hare's ear in multiple sizes, shapes and colors is an excellent nymph to have in a fly box. Tie the Hare's Ear Nymph.

The copper John. This pattern is relatively new, but has taken the fly fishing world by storm. It is the most popular fly pattern one large fly manufacturer has ever introduced. One of the reasons the fly works well is the weight of the fly. The bead head, copper wire body and lead really gets this fly down quickly and keeps it near the bottom where fish feed on mayfly nymphs. The pattern is probably better in larger sizes than smaller ones, but can be used as small as size #22 if you like. Tie the Copper John.

This is my old one-feather fly. It is best tied and fished in small sizes and in shallow water. A great BWO imitation, the fly works well during Fall and Winter fishing conditions. A variety of colors are achieved by using varying feathers to tie the fly. The entire fly is tied using one feather!

When and how to fish mayfly nymphs. As soon and as often as possible, of course; that's always the best time to fish.

Mayfly nymphs are almost always available to trout. The immature bugs will often break free of rocks and cover and drift along near the bottom of the stream. Greedy trout will always take advantage of a free meal, so they eat them.

When you arrive at a stream and do not see any surface feeding activity, try tying on a mayfly that is the size of what is available to the fish. During the Fall, Winter and Spring, this means using smaller - size #18 and smaller - mayfly imitations such as a Pheasant Tail or One-Feather Fly, with or without beads and/or weight. During Summer months, PMD and Green Drake nymphs will be readily available. The flies are larger, so imitation should be from a size #10-16 or so.

The difference between a successful and unsuccessful nymph angler is this: one more piece of lead. The fly has to get on or near the bottom of the stream in order to work well. This is where the fish are holding and feeding when surface activity is slow. Remember that 90% of feeding trout will probably be in 10-15% of the water, so find the spots in which trout are feeding and fish there.

I hope you do not take offense at that. If we don't care about our fish, who will?

Rigging: As mentioned, one more piece of lead. You have to have enough weight to get nymphs on the bottom of the river. How will you know? Every third or fourth cast, the fly should probably get hung up on the bottom. If it never gets hung up on the bottom or a fish, there is probably not enough weight. Use common sense, and make adjustments. Keep trying; never give up.

For lower and slower water conditions - they usually go hand in hand, after all - use longer, lighter leaders and tippet. Begin with a 7-1/2' 5X and add 18" of 5X tippet material. Above the knot at the leader/tippet connection attach lead - or tin, as the case might be. Tie your fly on. If you want to fish two flies, which is not a bad idea at all, make the first fly a bead head that is slightly larger. To the bend of the hook of that pattern attach 12-20" of 5X tippet and a slightly smaller nymph. Be careful casting: two flies may work better, but they also make better knots and confusion. If you need to use a bobber, 'er strike detector, attach it about two times the depth of the water above the lead. This will help you control the drift, and at first you should probably use one. Eventually, I'd encourage you to drop the bobber system and fish the water by sight and feel. This is both fun and rewarding. Bobbers are fine in the beginning, but they are not elegant to cast at all. Enjoy.

When fishing deeper and faster water, begin with a longer, heavier leader and follow similar advise. I'd encourage you to use a 9' leader that tapers to 4X, and add tippet material according to the size of the fly you will be using.

Begin fishing with short casts. Control the line and the drift of the fly. When fishing with nymphs, try facing across the current. If you are right-handed, stand on the left side of the river as you face upstream. Cast upstream at a 45° angle an keep the rod tip relatively low. As the current floats the fly back to your position, lift the rod tip at the same speed as the fly is drifting. As the fly drifts past you, drop the rod tip. Keep the fly in the water as long as it is drifting naturally. When the fly begins to drag - or when you can not tell where it is - cast again.

To cast with lead, bobber and two flies, allow the drift to get completely below you. Point the rod tip at the fly, then turn your body so you are facing the target. Gently lift the rod tip to pull most of the leader out of the water - the current will still be putting pressure on the rod tip - and gently accelerate the rod forward to a stop, stopping the tip so it is aiming at the target. Most of the time you will create a relatively open loop by doing this, which will keep the lead/flies from hitting the tip of the rod. If you do hit the tip, just drop the tip more on the forward cast.

When fishing faster water, the fish will often set the hook on their own accord when they take the fly. After all, they have to make a quick decision and will often strike very quickly. In slower water the take will likely be more gentle and subtle. Watch where the fly is in the water for a flash as a fish takes the fly, or for the strike detector to move or hesitate on the water.

Set the hook in the same manner as the fish takes the fly. If the fish hits it quick and hard, set with a quick motion, as though you are making a quick pick up of the line for a new cast. If the fish takes the fly slowly, gently lift the rod and then set the hook with a quick movement of your wrist of forearm.

There are many other ways to fish with a nymph, and I will add to this section as time and interest allow. It is time to move on to fishing mayfly emergers. Here we go.

As you'll recall, mayflies emerge on or near the surface of the river - most of the time. There are mayflies - our Green Drakes, for example - that emerge on the bottom of the stream and move to the surface as adults. We're going to talk about fishing the bugs that are moving to the surface, break through the meniscus - which is the surface film - and climb out of their shucks upon arrival.

This picture shows a mayfly climbing out of its shuck. Isn't that amazing? When the do this, they go from assimilating oxygen through their gills, to taking oxygen from the air in breathing tubes. Amazing stuff, that. As you can see, the bug is almost out of the shuck. The shuck has become translucent and is trailing behind the bug. In a few moments this bug will be out of the shuck, floating along the surface of the river as an adult until the wings are fully dried, when it will fly off to the bushes and molt.

As the bugs move toward the surface, the fish feed on them. There are often thousands of bugs coming off, and the fish will generally concentrate their feeding activity where the bugs are most concentrated. That makes sense. Trout are opportunistic and greedy, and they want to get fat. That means eating lots and moving little. The fish may have been feeding on the nymphs in deeper water, but they'll move towards edges and shallower water to feed on emerging mayflies, so they do not have t move as far to get them.

When the bugs are moving towards the surface, they are moving. Duh. The pattern above, which is a soft hackle, is a great imitation. The thin body imitates the nymph, while the soft hackle on the front of the fly imitates the legs thrashing about as the bug is swimming/floating to the surface. This pattern also works well when fished on the surface, as many bugs - actually, most of them - do not emerge successfully. A soft hackle looks like a dead bug, or an emerging bug.

Fish the soft hackle emerger wet and at the depth the fish are most actively feeding. Often, adding a bit of movement to the fly will bring vicious strikes as the fish grab the bug and return to their feeding lie.

When the bugs arrive on the surface, the shuck splits and the bug climbs out. The shuck is trailed behind the bug in the process and somehow the fish know that this bug is vulnerable, and cannot fly away. The pattern above, called a spotlight emerger, shows the trailing shuck - the shiny gray material in the back of the shot - and the wing/legs coming out. The fly fishes very well in the surface, or just below the surface film. If you are tying your own, use soft hackle for the wet style, and rooster hackle for the dry. This one shows the rooster.

As the bugs get out, the wing may still be slightly compressed, which the next pattern imitates well. Note the split tail of an adult, and the ball of wing and dry fly hackle. Fish this fly dry, and as an adult.

The adult may be imitated in a variety of ways. Please see our adult mayfly picture above. Standard and traditional dry flies (at left), parachute imitations (below) and thorax patterns (not shown at this time) all work well to imitate adult mayflies.

The size and shape of the fly are most important. Color matters when it matters. You'll have to figure that one out on your own. Often, there is a difference between a dubbed body and a quill body. I'm not sure why, but perhaps the silhouette that is created by the shape of the fly makes a difference in the confidence in which a trout eats the fake. Who knows? We'll just have to do more on-stream study to figure this out.

Both parachute and thorax patterns float lower in the water. Sometimes this as an asset, and sometimes it is not. Again, experiment and keep on fishing.

For the most part, fishing emergers and adult imitations is about the presentation of the fly. The pattern has to float into the trout's window of vision so they can see it, and usually it should float into this window with the current, and without drag.

Presentation, then, is about getting the fly into the right spot so it will drift with the current to the right spot. Fishing a spinner - shown at left - is going to be about the same. Please read on.

Rigging: I'd encourage you to begin with the shortest, heaviest leader you can get away with, and still make a good drift of the fly. Use the same formula as we did with nymphs for determining the size of the tippet material. Why a shorter leader? Make the shortest casts that you can, getting as close to the feeding trout as you can. If the fish reject your fly - they will turn toward the surface and the fly, then turn away - add tippet length. If you started with two feet of 5X, make it four feet and try again. If that does not work cut the 5X back to about two feet and add about four feet of 6X. I often use upwards of six to seven feet of tippet when fishing dry flies, in order to get the proper drift of the fly.

Presentation is the topic of another day, and we'll cover it soon.

I hope this helps you select and fish the right fly when mayflies are emerging. Together, this information compresses many years of angling, tying and observing on my part. If you have questions about any aspect of this, please drop me a note at angler@peakpeak.com. I'll answer as quickly and thoroughly as possible.