Matching the hatch

The expert fly fisherman is adept at identifying natural flies in the air and on the water and is quick to choose the right artificial; and a degree in entomology isn’t necessary.

Arriving at a river on a fine spring day, the dry-fly fisherman looks for a rising fish, and having located one decides what kind of fly it is feeding on, so that he can present a suitable artificial. Matching the hatch requires a knowledge of the en-tomology of the particular river, assisted by the ability to identify flies. But this is not the daunting proposition it may at first seem.

Upwing, caddis and midge

Although trout take many kinds of fly, the dry-fly man need concern himself with three main categories —upwinged flies (commonly called ephemerids), the caddis (or sedge) family, and the midge family. Apart from these there are reed smuts, alder flies and some land flies which get blown onto the water.

Upwinged flies, of which there are many species, have an interesting life history, which it is necessary to understand. An ephemerid has two winged stages, in the first of which it is called a dun, in the second a spinner. Duns are easy to identify as they sail downstream with their wings erect like little yachts, but trapped the day before.

Having decided whether the trout are taking duns or spinners, you must rely on colour and size to distinguish species. Most of the ephemerids bear names referring to their colour—olives, iron blues, pale wateries, blue-winged olives and yellow uprights. All of these have duns and spinners, but only occasionally do the two stages have dif- ferent names. For example, the olive spinner is often known as the red spinner because of the distinctive colouring of its body.

Most of the olive duns are various shades of olive green with smoky grey wings. There are various sizes, but as a general rule the size of the fly diminishes as the season progresses, until late June, after which there are few flies about and it is rare to see any until September.

In addition to Rough Olive, Medium Olive and Olive Quill, the following patterns represent olive duns. For the larger flies, the Gold-ribbed Hare’s Ear, which imitates the hatching dun, is excellent when fished in the surface film, half-in and half-out of the water. Greenwell’s Glory simulates the smaller olive duns which appear from March.

Pale Wateries and Iron Blues

During May or later, trout will suddenly start refusing olive dry flies and, if you carefully observe the water and the air above it, you may see some smaller flies with which the fish are preoccupied. These insects are pale wateries, so change your fly.

Pale water duns are buff or golden olive, with paler wings of a light sandstone shade. Two sizes are usually abundant from May to September. Pale wateries are to be found on most rivers where the flow is not too sluggish.

As well as the Pale Watery dry fly, Ginger Quill, Tup’s Indispensable and Lock’s Fancy are the patterns to use. Tup’s Indispensable is tied with a pinkish dubbing and is quite bulky. Although it does not appear to match the colour of the natural fly, it retains air bubbles when wet, which add an attractive sparkle.

The iron blue is a small, dark slate blue fly. It appears from April to September and hatches in great abundance on wet, blustery days. When iron blue duns appear there is no mistaking them and the artificial to put up is either an Iron Blue or a Dark Watchet. These duns are about half the size of a medium olive and sometimes appear almost black. Be sure to have some Iron Blues in your fly box, for when these flies appear, the trout will ignore everything else. A mole fur dressing will match the colour exactly.

The blue-winged olive is like the ordinary olive, but has blue wings which are taller than its body is long. They are found on the water from May to September, but are most common in July, August and September. The blue-winged olive is notoriously difficult to imitate—at times the standard patterns will not provoke any response from trout at all. This may be because these duns appear during the evenings when the effect of the light makes imitations look unreal to the trout.

The famous Itchen fisherman GAM Skues advocated the use of an orange fly to imitate both dun and spinner of the blue-winged olive, and this has yet to be bettered.

Ephemerid spinners are somewhat easier to sort out because the majority of the females are various shades of red-brown. On the water, the spinners of olives, pale wateries or iron blues are all similar shades. So you need a very small range of flies.


Have in your box a selection of the following ephemerids in several sizes from 12 down to 18: Red Spin- ner, Pheasant Tail, Lunn’s Particular, Houghton Ruby and, for the blue-winged olive, Sherry Spinner and Orange Quill.

There are two other important species of ephemerid—the mayfly and the caenis, or ‘fisherman’s curse’. The unmistakable mayfly is the largest of the upwinged flies and on chalkstreams where nymphs are banned, its imitation will sometimes bring up the largest fish, which lie on the bottom and are only tempted by larger morsels.

Trout take the different stages of ephemerids in various ways. When they are feeding on duns you will see the fish’s head come out of the water and you may even see its jaws engulf the fly. Spinners can be sipped in by the biggest of trout leaving only a tiny dimple on the water’s surface to mark the event.

Twilight eruptions

During late spring and summer, caddis flies or sedges appear. These are much larger than the ephemerids and most of them hatch during the late evening, causing trout to rise with great eruptions in the water. With their distinctively shaped opaque wings they are easy to identify and should not be confused with the alder fly, a day-flying insect with transparent wings.

Artificial caddis are known by the same names as the natural—the Cinnamon, Medium, Great Red and Little Brown Sedge. The Welshman’s Button and Lunn’s Caperer, commemorating eminent anglers, are also sedge patterns.

Trout feed unselectively on sedges, taking them with gusto, not waiting to inspect them as they do the ephemerids. Pattern is therefore less important.

The reed smut is significant for its abundance on many lowland trout streams and appears in June and again in September. Loosely termed ‘black gnat’—the name covers a multitude of black flies—reed smuts are found in dense clouds, whizzing to and fro just above the surface. Trout take them in the air, by jumping, and on the water during the insects’ egg-laying.

Although there is no recognized standard pattern available that represents the reed smut, Iron Blue or Blue Upright will often work well on many waters.

Midges, if they attract trout at all, are taken at the pupal stage, below the surface, for as soon as the hat-ching fly reaches the air it is able to take off. On certain rivers, trout rise to tiny black or green chironomid (non-biting) midges, but their size makes them hard to imitate. However, small Black Gnats work at times and, for the green fly, the artificial Green Midge, tied on a No 20, has caught very large trout. You could also try a small Grey Duster when midges are about, instead of struggling to tie facsimiles.

The Grey Wulff

Recent interest in trout fishing has been largely centred on stillwaters, it is there that we find the majority of new patterns. However, one in-novation designed more specifically for river and stream fishing should be mentioned here: the Grey Wulff. The peculiarity of this fly is the way the wings are positioned—sloping forwards over the head of the fly. Instead of feather quill, the wings are tied with a bunch of hair fibres. This makes the fly a remarkable floater and can successfully imitate almost every upwinged fly.