DF17. The March Brown Dry Fly

THE MARCH BROWN FLY PATTERN
It is peculiar that this pattern should include the month of March in it's name since the natural insects are not confined to hatching in this month. These flies represent the two different insects that are commonly given the same name: the March Brown (Rithrogena Germanica, its old scientific name was Rithrogena Haarupi) and the Late (or False) March Brown (Ecdyonurius Venosus). The March Brown likes large stony rivers just like stoneflies. This is why in England it is completely unknown on the Southern Chalkstreams and stillwater lakes or ponds.  Hatches are often on a grand scale in the middle of a spring day. The March Brown pattern is one of the oldest angling flies around. Look for hatches of the March Brown in the late spring just after lunch time. The Late March Browns hatch in early summer after the March Brown hatch. It is slightly larger and far less numerous than its earlier hatching insects. Some years may bring a late season hatch if there is hot weather. It is the emerging nymphs of this mayfly that are regularly eaten by trout, but duns and egg laying female spinners are also taken. 

After hatches of tiny midges and Blue winged olives the March Browns are normally the first large mayflies of the year. They always seem to hatch in cold rainy afternoons. They can hatch from mid February and continue into May. If you are in the water earlier in the day try floating a few nymphs like the Gold Ribbed Hare's Ear or a larger Pheasant Tail near the bottom and as the morning develops present them nearer and nearer the surface as the nymphs float upwards ready for the hatch. As soon as you see surface rises switch to a dry fly. The Autumn Dun (Ecdyonurus dispar) is often confused for the March brown insect as the two are of similar size and appearance. It also favors stony or boulder-strewn rivers as well as the shores of stony lakes. The duns emerge during the day from mid to late summer. Treat your fly with floatant and let it drift on the water surface with the current or use small jerks to impart the appropriate movement of a struggling drowning fly. You can also let it sink slowly moving only slightly to indicate the insects dying twitches. When these floating fly patterns come on the water they evoke considerable interest from the fish. These big flies do their best work where rivers and lakes are bordered by heather or trees. Remember you are trying to imitate a drowning land based insect. There are a number of variations on the standard pattern. We have found the bigger hook sizes were more productive in catching trout.

The March Brown pattern has been tied by fly fishers over the centuries. As far back as the 1600's it is recorded as being a fly pattern of choice in England. The fly is known by many different local names like Brown Drake, Dun Drake or Cob Fly. This fly pattern unusually works when there are no hatches. It seems to function as a universal attractor pattern for dark insects. G.E.M. Skews wrote "..is an excellent fly and as generally tied, quite a poor imitation of the natural fly and quite a passable one of almost anything else." The nymph remains at the bottom of the river bed for over two years undergoing a series of moults as it grows. It has a flattened body which appears broad in proportion to its length. It is large and dark in colour. A large Gold Ribbed Hares Ear Nymph or a Pheasant Tail nymph is an ideal choice as a match for the March Brown Nymph.. The natural nymph can swim but spends most of its time sheltering under rocks and stones at the bottom of the river or stream bed. It feeds mainly on algae in these relative safe locations and is only in danger of being eaten if it is disturbed. Wriggling Salmon, laying eggs in the gravel can abruptly force the March Brown Nymph into open water where it has to quickly find a new home. Trout and Steelhead lurking downstream to catch stray eggs will also gobble up unfortunate March Brown Nymphs.  

I like to use a Soft Hackle Spider fly to replicate the action of the Early March Brown nymph swimming to the surface. Either side of the hatch I often use one as a top dropper on a rig of three with two other nymph patterns down below. The takes do not tend to be as splashy and quick as the trout have realized that the crippled, drowning and trapped insects are not going to suddenly fly away. So they can take their time. I try to drift these rigs over areas of fish activity with regular 'dead drift'. On reaching the surface the the nymph case is held in the water film as the dun emerges, pumps blood to its new wings, dries quickly and then flutters off into the air. A Suspender Buzzer is ideal as a imitation of this stage in its life cycle. The False or Late March brown nymph crawls from the river to the land to hatch. As soon as the hatch appears I switch to the dry fly. Look out for bird activity as a great indicator that it has started.

I have noticed that on the first few days of the hatch for some strange reason the fish seem to stick to the smaller olives and shy away from the bigger march Browns so I always have a few BWO's handy. They soon get over this fear and happily feast on the bigger flies. If the hatch occurs in fast flowing water some of the duns will drown and trout can be taken on a March Brown Wet Fly. The dun has brown mottled wings where as the later spinner has lighter nearly transparent wings. The males swarm close to the water and after mating the female returns to the water surface to deposit the eggs. The adult males are rarely taken by fish. It is these egg depositing females that are looked upon as a good meal by trout. Trout being opportunists feeders will take struggling spent spinners of both sexes, caught in the surface film.

DRY FLIES
The dry fly is designed to float on the surface of the water. To prevent it sinking, water repellent hackles are wound around the hook to distribute the weight over the surface of the water. The hackles also simulate the legs and splash of an aquatic or terrestrial insect trapped on the water surface. Most Dry flies are deceivers designed to imitate a specific natural fly like the crane fly, ant and hopper series of flies. Other flies like the Adams are more general designs that are just intended to produce an edible looking fly.

Dry fly fishing has always been regarded as the supreme art in fly fishing circles. Accurate presentation of the fly can be essential. Trout will rise to a variety of natural flies but as far as the dry fly fisherman is concerned the mayfly hatch has to be the favored time. In almost all instances where trout feed on drowning insects the rule is not to move the fly. An imitation is far more likely to succeed if it is cast out and then left. So long as it is cast in the right spot.

The color of the fly is always important when matching the hatch, then size is the next important decision. The artificial fly does not have to be a precise imitation of the natural insect, but what is important is how and where it is presented in relation to the depth of water. This includes the height at which the fly floats above the surface of the water. Some fish will greedily take flies that are floating in the surface but ignore flies that are floating above it and visa versa depending on the conditions that day. Use your eyes to see which natural insects the fish are taking. A high-floating dry fly will have more chance of being taken on a bright day because of its visibility, but if it does not dent the surface film on a dull day it will be less effective. A fly floating in the surface on a sunless day leaves a much more visible halo of outlining light which surrounds it.

Always try and get the leader immediately in front of the fly to sink under the water as this makes it harder for the fish to spot. This can make the difference between a blank day or one with lots of action. When putting on floatant make sure you keep it off the leader. This is a common mistake that can affect your fish catching chances. Degrease the front 10 inches. Do not try and fish this pattern downstream as it will drown. Fish it upstream and look in front of you for where the fish are rising for the natural insect. Be observant. If the trout start to dine on spent spinners rather then duns consider changing fly patterns.

MAYFLIES

Some adult mayflies hatch throughout the year but other species hatch only during certain months of the year. The term Mayfly applies to all members of the order of insects not just those that emerge in May. There are hundreds of fly patterns tied to imitate the many different mayflies and stages of their development. The natural insect belongs to the group of insects called Ephemeroptera. Ephemeros means 'lasting a day' and peteron means 'a wing'. Mayflies have cylindrical bodies, slender legs and two pairs of veined wings which are held vertical when at rest. They are found all over the world and are commonly called up-winged flies in some areas. The adults do not feed and live for only a very short time: most less than a day and some only for a few minutes. 

The aquatic Mayfly nymphs moult anything from 12 to 50 times and take up to two years to reach adulthood. In any square yard or meter of a stream there may be a few hundred to many thousand mayfly nymphs. They are an important part of any predator fish's diet. The fully grown nymph swallows air and floats to the surface where it emerges into the subimaginal stage. The Dun sits on the water surface for a few seconds after hatching to enable the blood to pump up it's wings and for them to dry. The colder the weather the longer this takes. It is very vulnerable to attack at this time from under the water surface. On windy days, gusts can topple over the drifting duns and drown them. If you cannot see any rises for surface floating duns during a hatch on windy days the fish are feasting sub surface on the unlucky sinking drowned duns as well as the emerging nymphs. Try using a partridge and Yellow Soft hackled spider wet fly, Gold Ribbed Hares Ear Wet fly, Blue Dun or Light Cahill wet fly to imitate drowned duns, depending on the local insects body color that can range from pale yellow, olive to tan. Wing color also varies throughout the world from pale gray to pale yellow. I often fish these wet flies on a dropper about 18 inches behind a dry fly. The soft hackle or wet fly imitating the drowned dun often catches the fish when nothing else works.

If the drifting newly emerged duns have not been eaten by a fish during this vulnerable time, they fly off and hide on the surrounding vegetation. Within 24 hours the duns molt into spinners and and are ready to mate. Mating swarms are formed by the males to attract females. They also occur at dawn or dusk to reduce the chances of single insects being taken. When a female flies into the swarm she mates with a male. The males fall onto the water spent and drown. They are known as 'spent spinners'. The females return to the riverside vegetation for a short period whilst the eggs mature. When the eggs are ready the females fly out over the water, dip into the water, lay their eggs and then fall into the water spent.  Some females species swim down to attach their eggs to submerged vegetation or objects. Others just land on the water surface making tempting targets for hungry trout. Try and scoop up a natural spinner floating dead in the water surface and match the body color with a parachute dry fly like a Greenwells, Tup's Indispensable or Gold Ribbed Hares Ear Parachute.