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Harbingers of spring

By Peter Lapsley

Peter Lapsley describes the river fly fisher's four harbingers of spring – the March Brown, the grannom, the Large Dark Olive and the Hawthorn – and ties the March Brown Nymph, March Brown Spider, March Brown Emerger, March Brown Dun, PT&HE Nymph, Goddard's Super Grizzly, Grannom Pupa, Grannom Dry and Hawthorn Fly

April is the first month in which the fly fisher may head for the water with any real expectation of success.
April is the first month in which the fly fisher may head for the water with any real expectation of success.

The opening of the trout season in March in some parts of the country is, in truth, more of an acknowledgement of impending spring than an invitation to fish. Trips to the river so early in the season have more to do with hope than expectation. Two things need to happen before that can change. The trout have to recover fully from spawning and the rigours of the winter, and the water temperature has to rise to a level at which both they and the insects they feed on begin to stir themselves. Nowhere in Britain do those things usually happen until mid-April, a magical month in which we may at last head for the river with reasonable optimism.

Identifying the flies that appear in April is not difficult. There are really only four species that are widespread and of consistent interest to trout and anglers alike, and identification is simplified even further by the fact that there are few areas in which all four occur.

The first is the March brown (Rhithrogena germanica), a creature of fast-flowing, stony, rain-fed rivers, which largely confines its British distribution to Scotland, Wales, and the North and West of England.

Trout don’t do Latin, and neither do I, but it is worth including taxonomic names so that we may be sure that we are all talking about the same insect. There is another British fly confusingly named the late March brown (Ecdyonurus venosus), which looks not dissimilar to Rhithrogena germanica. Found only in quite small areas in parts of Wales, the West Country, Northern England, and parts of Scotland and Northern Ireland, it appears chiefly in late summer and hatches tend to be very sparse.

American readers may wish to distinguish our March brown, also, from their ‘Western March brown’ (Rhithrogena morrisoni), which, in central and North Eastern states, appears at about the same time as Rhithrogena germanica. Although the female is much lighter in colour than her European counterpart, the male is similar in both size and colour. So, while I have never tried it, it seems not unreasonable to suppose that a British artificial might be as effective in the US as it is here.

The best March brown hatches I have seen have been on the Usk during the first fortnight in April, their drama being emphasised by the complete absence of any other surface flies. One minute the water looks dead; the next it is covered with flies and with the rings and bulges of fish feeding at or just below the surface. Although they may be spread over two or three hours through the middle of the day and into the early afternoon, hatches themselves tend to be spasmodic and quite short, often lasting for only a few minutes, creating a real sense of urgency.

Several angling entomologists have said that when March brown hatches occur the trout tend to feed on nymphs and emergers, rather than on winged adults. That has not been my experience and may be rather too much of a generalisation. While it is certainly true that the fish will cheerfully take an artificial nymph or emerger during a March brown hatch, and that a nymph can be useful during lulls between hatches, I have had considerable success with an artificial dun once a hatch has become established – and it is always particularly satisfying to take fish on dry flies so early in the season.

Lunchtime olive
The second early season fly that can bring trout to the surface and joy to anglers’ hearts in April is the large dark olive (Baëtis rhodani). Widespread and abundant throughout the British Isles, it compensates fly fishers in the Midlands and the south of England for the absence of the March brown from their waters.

Confident identification of the large dark olive is quite simple because, apart perhaps from the March brown, it is almost always the only fly on the water during the first half of April, and the two species differ substantially in size and wing colour. The large dark olive is only about three quarters of the size of the March brown, the body of which is about 12mm long. And, more readily noticeable are the large dark olive’s pale grey wings which contrast sharply with the mottled brown wings of the March brown.

The description of it as ‘the large dark olive of spring’, so often used by angling writers, is misleading. Riparian owners, keepers and entomologists will tell you that large dark olive hatches actually begin in the autumn and continue spasmodically right through the winter, eventually petering out in mid- to late April. Fly fishers are so rarely at the waterside during the winter months, though, that they tend to be unaware of this. Finding large dark olives hatching when they begin fishing again in April, they understandably suppose the hatches to be confined to a couple of weeks in April.

A far more informative label would be the ‘large dark olive of lunch time’, for its hatches almost invariably occur between noon and 2:30pm, when many of us are tempted to sit on a log and munch away at our sandwiches. To do so can be a mistake. Where they occur, large dark olive hatches can be amongst the best in the season and the trout can respond to them with great enthusiasm, so it can pay to postpone lunch until mid-afternoon.

Nymph opportunity

On rivers with healthy populations of large dark olives, advantage of predictable hatches can be taken by fishing a nymph for an hour or so before the hatch begins. As is the case with all the Baëtids, the large dark olive nymph is an ‘agile darter’ – slim, streamlined, and swimming strongly with undulating movements of their abdomens, rather like the abdominal and leg movements used by human swimmers doing the butterfly stroke. It seems probable that the nymphs make several forays towards the water’s surface before eventually allowing themselves to become trapped in the surface film and hatching.

It is often said that trout are more inclined to take large dark olive nymphs or emergers than winged adults. Maybe. It is certainly true that trout take the artificial nymphs and emergers very enthusiastically. But having experienced countless large dark olive hatches, during which I have had great sport with high-floating Kite’s Imperials and John Goddard’s Super Grizzlies, which I now prefer, I would be wary of being too adamant about it.

The third fly seen on many rivers in central Southern and South West England, in Wales and Yorkshire, on the Ribble and the Eden, and in parts of Scotland, is a caddis fly, the grannom, (Brachycentrus subnubilis). It can be frustratingly localised, not just to individual rivers but to particular stretches of those rivers. Where it does occur, the hatches may last for anything from a few days to a couple of weeks, running from mid-morning to mid-afternoon.

Back in the early 1980s, I was fortunate to have a rod for four years on two and a half miles of the lovely little river Ebble, to the south of Salisbury, between Coombe Bissett and Odstock – unstocked, very lightly fished and with a wonderful head of wild brown trout to about a pound, or sometimes a tad more.

I had only just put up my rod on my first day of my first season when, quite suddenly, clouds of grannom filled the air and the entire piscine population of the river went berserk. The naturals were instantly recognisable by the fact that the grannom is, by a month or more, the earliest sedge to appear on the water, and by the bright green egg balls carried beneath the last few segments of the females’ abdomens. I had no specific grannom pattern in my fly box but tied on a dry Wickham’s Fancy and had a field day.

That evening, I read everything I could find about the grannom in my library. Courtney Williams in his Dictionary of Trout Flies said that, during a hatch, the fish were often as enthusiastic about the pupa as about the adult. He evidenced some confusion about the difference between the larva, a creature which creates a case for itself which it drags around on the stream bed and amongst the weeds; and the pupa, small, free-swimming and entirely different from the larva in both appearance and behaviour. And he offered only one pattern, GEM Skues’s somewhat questionable dressing for the ‘Grannom Nymph’, whatever that may be. With a body of bright green tapered wool and a rich brown partridge hackle, it sounded to me like an indifferent attempt to represent the larva, rather than the pupa.

Deadly larva
Halford’s Floating Flies offered only a ‘Grannom Larva’ which bore no resemblance to a grannom at any stage in its life. And my other ‘bibles’, JR Harris’s An Angler’s Entomology and John Goddard’s Trout Fly Recognition were effectively silent on the subject.

Undaunted, and determined to tie a reasonable representation of the larva, I cobbled one together myself – a small, fairly typical ‘sedge pupa’, lightly weighted, with a slender body of golden olive seal’s fur dubbed over flat gold tinsel for ‘translucency’, a slightly darker thorax, a simple wing case and a couple of turns of cream cock’s hackle. Over the next few days, it proved deadly.

Later, I tied some adult Grannoms to a pattern by Pat Russell, a great fly fisher and a lovely man, who lived close by and occasionally fished my water.

For a week or ten days in April during each of the following three seasons, those two patterns proved as consistently reliable and effective as any I have ever used. Then came a pause. Moving from Hampshire to London, I waved a sad farewell to the Ebble and, for the next 16 years, was privileged to have a rod at Abbotts Barton on the Itchen. While a wonderful fishery in every other way, and beautifully run, I never saw a single grannom there, and the artificials were soon eased out of my fly box.

At the end of 2003, I left Abbotts Barton and joined a club with several miles of fishing on the delightful River Meon – in many ways, almost a clone of the Ebble.

On my second visit, in April the following year, I was slightly surprised to find myself fishing through a very respectable grannom hatch; not the sorts of blizzards of flies I had seen all those years ago, but more than busy enough to bring the fish enthusiastically to the surface. Once again, I had no specific artificial with me, but pressed a little Ek Hair Caddis into use, and it worked.

In vain

Now, with a rather larger library of entomology books and with Internet access, I hoped to find a proper description, or even a photograph, of a grannom pupa, but searched in vain. Given the localised nature of grannom hatches and the probable rapidity of the transformation from larva to pupa to winged adult, I have to confess to wondering whether any of the entomological gurus have ever actually seen one. So, I went back to my tried and trusted patterns, still uncertain as to whether the Pupa I was tying bore the slightest resemblance to its natural counterpart.

The following week, and each April since then, Pat Russell’s adult and the Grannom Pupa worked, every bit as well as they did on the Ebble, and I now never go fishing in April without half a dozen of each tucked away in the box.

And before you ask, yes, I have tried spooning trout taken during grannom hatches without ever finding anything recognisable as a pupa amongst the dark mass of their stomach contents.

The fourth fly in the catalogue of ‘harbingers of spring’ is the hawthorn (Bibio marci), so-called because the female usually puts in her first appearance around April 25, St Mark’s day. The males, which are smaller than the females, sometimes show up a few days earlier. The hawthorn seems to be very much a ‘morning fly’, busily in evidence until midday or very early in the afternoon and then disappearing completely. Its hatch usually continues until the end of the first week in May, when it ceases quite suddenly.

Hawthorn flies are terrestrials, their larva feeding on the roots of grasses and on decaying vegetable matter. They are therefore unaffected by the general malaise – the combination of siltation and diffuse pollution – that has so depleted aquatic invertebrate populations in so many British rivers over the past 20 or 30 years. Indeed, my own impression is that hawthorn hatches have been becoming increasingly prolific, but that is not to say that they necessarily offer certainty of success.

In order for trout to develop an appetite for hawthorns, at least some flies have to be blown onto the water. Although they are pretty inept flyers and are therefore much at the mercy of the wind, this does not always happen. The unmistakable big, black bumbling, dangle-legged insects tend to congregate in clouds on the sheltered, downwind sides of hedges and coppices and, on still days, may never venture anywhere near the river. Only when there is a stiff breeze blowing in the right direction, and ideally a scarcity of shelter from it, do splendid crash landings on the water occur in significant numbers.

Many years ago, the late Peter MacKenzie-Philps told me that, rather than riding high on the surface film, hawthorn flies blown onto the water slowly subside into it, eventually floating flush with the surface but not actually sinking. If you watch them, you will see that to be true, and it has a significant bearing on the design of the ideal artificial Hawthorn Fly.

By the time the hawthorn hatch is over, a raft of other flies are beginning to put in their appearances – medium olives and small spurwings; then, if we are lucky, iron blue duns; and there are only a couple of weeks to go to the beginning of the Mayfly, but that’s another story.

Nine flies:

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