Fly Fishing and Fly Tying: Day-Flies

This is the most important — although not the largest — group of anglers’ flies. It includes the Olives, Iron Blues, March Browns, Pale Wateries, Mayflies, and Blue-winged Olives.

Specimens of these flies are found in most clean running water in Britain. Some species, however, tend to be localized, conditions sometimes favouring one at the expense of another.

All day-flies have a similar life-cycle. The nymphs emerge from eggs deposited, usually in shallow water, by the parent fly. A stone turned over at the edge of a stream nearly always uncovers one or two day-fly nymphs, which may be seen scuttling for shelter. Nymphs hatch into flies by first swimming or drifting to the surface. The fly must then free itself from the nymphal skin, or ‘shuck’, during which operation it is quite defenceless and falls an easy prey to fish. Once free of its shuck, it flies off the water as a dun. The drier and warmer the weather the quicker the fly can leave the water and thus escape the trout.

The dun stage of the fly’s life is of varying duration according to the weather and may be minutes or even days. Sooner or later, however, the dun — which has now taken refuge amongst bank-side vegetation — is ready to shed its skin once more. In its final form it creeps forth as a spinner or perfect fly.

With day-flies, then, we have three distinct forms : nymph, dun, and spinner. To these may be added a fourth phase, that of the spent gnat; this is simply a spinner which has laid its eggs and sunk, dying, on the water.

Trout can be caught on artificials suggesting any of these stages. Broadly speaking, however, most fly-fishers are interested in dun and spinner impressions unless the fish are very obviously feeding on the other forms.

Natural flies must be considered in relation to the two main types of river system we have in Britain. These systems are : rain-fed streams and chalk-streams. Rain-fed streams usually rise in moorland; their flooding after rain and subsequent fall are often rapid. Frequently they are swift and stony. Chalk-streams rise from springs in the deep chalk strata. They are clear and slow-flowing and flooding is rare. They afford ample cover for huge numbers of day-fly nymphs. Rain-fed rivers on the other hand often offer little cover, since their weed-beds are sparse. Their fly hatches therefore are often meagre and patchy.

The rain-fed or rough-stream angler — and this includes something like ninety-eight per cent of British fly-fishermen —has a different approach from that of the chalk-stream angler. The former usually mounts a fly-pattern suitable for the day and the season. The latter often prefers to wait until flies hatch in the sheltered reaches he fishes and offer him a chance to identify them.

We will now consider the day-flies common to both types of river along with the fly-dressings which suggest them. This short list of day-flies starts off with the commonest of the Olives — the Large Dark Olive (LDO) or Large Spring Olive. Some Welsh and West Country anglers call this fly the Blue Dun.

The LDO is found throughout Britain. It hatches in the coldest weather and is very welcome to winter-starved trout. The LDO dun is a fly about half an inch long with bluish-grey wings and a brownish-olive body.

A good dressing for the LDO is the Blue Upright, a traditional Devonshire pattern. A Welsh friend with over fifty years of fly-fishing to his credit converted me to its use. There may be some difficulty in obtaining the correct hackle for this fly, which should be a dark blue game-cock hackle with stiff shining fibres — just one of the occasions when a cock’s hackle is used in a wet fly.

Body: Peacock stripped quill to give well-marked light and dark bands

Hackle: Dark blue game-cock

Tail: A few game-cock fibres

Hook: 10s and 12s (Redditch Scale)

The spinner stage of the LDO’s cycle is suggested by a simple Red Spinner pattern. When using a ‘team’ of three wet flies it is good practice to mount the Red Spinner as a bob-fly. Or a cock hackle can be used in place of hen and the fly fished dry :

Body: Red silk ribbed with finest gold wire

Hackle: Pale honey hen

Tail: Fibres of honey hen

Hook: 10s and 12s

The only other Olive the angler need worry about is the Medium Olive. True, the Small Dark Olive sometimes appears but a separate pattern is not warranted.

The Medium Olive is the Yellow Dun of our grandfathers. It is a smaller fly than the LDO, with blue-grey wings and a bright yellowish-olive body. One of the best patterns is the Rough Olive, another old West Country dressing:

Body: Olive seal’s fur, well mixed with a pinch of orange

Hackle: Dark blue hen

Tail: Fibres of blue hen

Hook: 12s and 14s

The March Brown is localized in distribution. There are heavy hatches of the fly on some Welsh rivers; in some other places it is seldom observed. It is a largish rather coarse-looking fly of drab, mottled appearance.

March Brown patterns are legion and catch fish even in water which never harbours the natural. This is almost certainly because the dingy brownish dressing suggests the hatching nymphs of several fly species. A useful pattern is the Hackled March Brown:

Body: Brown rabbit’s fur ribbed with finest gold wire

Hackle: Dark partridge

Tail: Pale mallard fibres

Hook: 10s and 12s

The Iron Blue is a small fly which enjoys cold blustery weather. Some anglers reap their best baskets of spring trout with an Iron Blue pattern, especially in April and May. Hatches are variable; sometimes heavy. Fish feed greedily on the nymph.

There are many dressing variations of the Iron Blue, but a simple and very effective tie is as follows :

Body: Tag of scarlet silk. Blue-grey mole’s fur ribbed with scarlet silk

Hackle: Light blue dun hen

Tail: Fibres from Rhode Island Red cock

Hook: 12s and 14s

The name Pale Watery is a convenient label for several similar species of flies, including the Sky-blue Dun, the Blue-winged Pale Watery, and the Pale Evening Dun. These creatures are as lovely as their names.

The Pale Wateries appear from mid-May onwards. They are medium-sized flies and always look most conspicuous when the light glistens on their wings as they rise from the water. The writer has enjoyed excellent catches using Pale Watery patterns.

Two dressings will be adequate for most anglers — a wet:

Body: Bright yellow silk ribbed with finest gold wire

Hackle: Pale blue dun hen

Tail: Fibres of a honey or white cock spade-feather

Hook: 12s and 14s

and a dry:

Body: Amber or pale orange silk ribbed with finest gold wire

Hackle: Stiff, shining honey cock

Tail: Fibres of honey or white cock

Hook: 12s and 14s


The Mayfly is the largest and best known of the day-flies. It seems, however, to be becoming less common and one frequently hears the complaint that hatches are not what they were. This may be due in part to the fact that, with deeper drainage and regular dredging, rivers are getting rid of their water much faster nowadays. Mayfly nymphs thrive in a habitat of mud and sand.

On chalk-streams the Mayfly hatch is an event of some importance. This is less true of rough streams, many of which — for example, the Usk — hardly know the May. I have, however, seen the Usk covered with duns of the Yellow May, a fly not much smaller than the May and probably just as succulent to the fish.

One Welsh river ends its course in flat country where suitable beds of muddy sand are retained. For two or three days each year there is an enormous hatch of Mays and the fish will look at nothing else. A few kilometres upstream, however, not a fly will be found.

The dun stage of the Mayfly’s cycle is known as the Green-drake. The spinner stage is known as Grey Drake (female) and Black Drake (male).

Of all the very many Mayfly patterns that have been devised, probably none is better than Goulden’s Favourite and its variations. This dressing makes use of the fact that the glittering wings of a hovering Mayfly appear to be orange when viewed in a certain light.

Here is a useful variation of Goulden’s Favourite:

Body: Olive `Raffene’ (artificial raffia) ribbed with scarlet floss silk (doubled)


First hackle : Dark Rhode Island Red cock

Second : Hot orange hen

Third : Grey mallard, left natural or dyed green

Tail: A few cock-pheasant centre-tail fibres

Hook: 8s and 10s (Mayfly hooks)

This pattern can be fished either dry or wet. Wet fishing is often useful at the tail-end of a spate, when Mays are hatching and getting washed down-river.

The Blue-winged Olive (BWO) is common to a great many rivers. On the Teifi it is almost the only day-fly to hatch in quantity during the summer. It is a largish fly with four conspicuous bluish wings and can be observed rising languidly from the water on thundery, airless days in July and August.

The BWO has the reputation of being a difficult fly to match successfully with an artificial. The truth is that trout can be mighty fickle in the heat of summer and unless there is a really heavy hatch of BWO they just don’t bother to feed.

In some conditions trout seem to prefer the BWO spinner to the dun, perhaps because they can see it better.

Here is a simple pattern for the BWO dun:

Body: Olive tying silk ribbed with finest gold wire

Hackle: Grey-blue game-hen

Tail: Brownish fibres from a cock’s spade-feather

Hook: 10s and 12s

The BWO spinner has long been dubbed the ‘Sherry’ spinner owing to its tawny colour. An excellent dressing is as follows:

Body: Ruddy fibres from a cock-pheasant centre-tail feather ribbed with finest gold wire

Hackle: Dark RIR cock

Tail: RIR cock fibres

Hook: 10s and 12s

18. July 2011 by admin
Categories: Fish, Game Fishing | Tags: , , | Comments Off on Fly Fishing and Fly Tying: Day-Flies


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