DF1. The Light Cahill Dry Fly

THE LIGHT CAHILL FLY PATTERN
From the middle of May to September, depending on where you live, hatches of different varieties of light colored mayflies now commonly known as Light Cahills can be found. This is a recent collective common name that covers many groups of the Heptageniidae family of mayfly insects. In the 1880's a New York railroad worker called Daniel Cahill developed a fly that became famous all over America, the Light Cahill. When he wasn't fishing or tying flies he was a brakeman on the old Erie and Lackawana Railroad. It is a great general imitation of summer mayfly duns. Just choose the hook size and color to match your local hatch. It was originally designed to imitate a family of mayflies with the name of Stenonema. They begin hatching in late May and continue through June. In smaller sizes the Light Cahill is a useful fly to imitate hatches of Pale Morning Duns, Pale Watery Duns, Spurwings, Pale Evening Duns and the Red Quill Mayfly. The Pale Morning Dun (PMD) hatch is normally in the summer and massive in numbers, triggering aggressive trout feeding. The hatch normally happens in slow, clear water. The PMD is normally best matched with a size 18 hook fly. The Red Quill mayfly is not as widespread as other mayflies but if they live in the river you are fishing, you will find that this fly is an important insect to have imitations of. The reason being is that they occur in large numbers when they hatch and these are the flies that the trout want. Hatches are normally in the afternoon.

Dan Cahill is also credited with the unscheduled stocking of some Eastern North American rivers and streams with Rainbow trout. The story goes that on one steamy hot summer's day Dan was working a Lackawana freight train north of Port Jervis.  The train's progress was blocked by a derailed work train. Part of the freight being carried that particular day was a large water container full of live stock rainbow trout. They were starting to cook. They would not survive the delay. Dan took action to save them from certain death. He talked his work mates into helping him carry them back to Calicoon Creek and let them go free.  It was almost a mile back along the tracks. Their offspring have eventually spread throughout the whole Delaware watershead. Art Flick in his book "Stream Guide to Natural and their Imitations" said of the Light Cahill pattern, "To this date I have never met a fisherman who had fished any stream where trout could not be taken on this fly. It is doubtful if any fly compares with it in popularity, especially in the East." Ray Bergman author of "Trout" in 1938 commented on the light Cahill, "If it was necessary to confine my assortment of flies to only two or three, this would be one of them." He stated that although it is particularly effective in Catskill waters and similar mountain streams it had served him well in Michigan, Wyoming and California. He said, it is a "killing fly."

CUSTOMERS COMMENT
I use these flies with success on rivers in North Georgia, Eastern Tennessee and Western North Carolina like the Hiawassee, Chattooga, Tellico and Davidson. They seem to work very well. The Light Cahill is easily my most favorite and productive fly. I usually use in size 14 - 16. Frank Booth, Gainesville GA 

YELLOW DRAKE MAYFLIES
A Light Cahill on a size 10 hook is a useful pattern to imitate the Yellow Drake Mayfly. Yellow, Green and Brown Drakes are not the largest mayflies of the summer hatches but they are certainly much bigger than the early Blue Winged olive and Blue Dun hatches of early spring. They belong to the Ephemeridae family mayflies. They have all a deserved reputation for producing great hatches that can entice large lurker trout to leave their lays and feed greedily on the hatching Drakes. When they do hatch their emergence is not a subtle event. After breaking through the surface film and their nymphal shucks these large duns struggle frantically to get off the water. This makes them very conspicuous and easy prey for both birds and trout. They float for long distances waiting for their wings to fill with blood. When the wings are fully inflated and dry these duns flutter furiously as they try to lift their large bodies into the air. This fluttering action often is the trigger for some violent strikes.

As nymphs all three species prefer slow moving water that has a river bed of fine sand, gravels or silt. During a hatch you will find the greatest concentration in these same areas. The slow moving water gives the trout a very clear view of it's target. The Yellow Drake is the last of the three Drakes to emerge. Their hatches are normally in the middle of June and extend up to the middle of August. They can be found in freestone as well as limestone rivers. The are sometimes referred to as the 'Warmwater Drake' Summer low water conditions and rising water temperatures do not appear to upset them. they just emerge later in the day. Large concentrations are rarely seen on the water. They emerge sporadically but the trout and bass know it is Yellow Drake hatch time. Drift a Light Cahill on a size 10 hook over a quiet pool in the early evening and see what happens. Be ready to set the hook.

THE DRY FLY
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.