For trout, Ephemera Danica represent the icing on the cake. Stonefly, midges, sedge and Daddies may excite, but mayfly get top billing. Just why this should be so can partly be explained by the insects size (bigger than most) but it also has a lot to do with the mayflies ability to hatch profusely even in the most foul of weather. The adult insect has its allotted timespan to appear and generally speaking, the carnival goes on regardless even in slicing north winds and horizontal rain!

Though anglers have for centuries known about the propensity of mayfly to spur larger, more cautious, trout into feeding avidly, a deal of myth and legend has grown up around these luscious lacewings. The first bone of contention relates to the exact name/classification of mayfly. Today most anglers draw clear distinctions between olives, stoneflies and the like, however historically anglers of old often called all large winged insects `mayflies'. This confusion probably resulted from naturalists tendencies to call the whole family of upwinged flies (Ephemeroptera) `May-flies'.

Colloquial names for true mayfly like the Green or Grey Drake have entered the fishing vernacular, however even today the odd misunderstanding can arise. American anglers are given to the mayfly/stonefly misnomer and in the UK some Border and Northern England river fishers still refer to big olives as mayflies!

If classifying the British mayfly is sometimes difficult, its distribution throughout this 'Sceptred Isle' has also been a subject for confusion. Whereas the southern chalkstreams and the Irish Loughs have long been noted for abundant mayfly, the fact that these insects are also well distributed across the northern highlands is frequently ignored. As mayfly larva requires a softish clay-like soil to burrow into from egg stage, it's often wrongly assumed that the apparently peaty stony rivers and lochs of Scotland do not provide suitable mayfly habitat. This is a big mistake, especially if you want to plan an angling holiday around times when larger than normal trout are to be caught.

Many highland lochs and streams contain valuable but not always visible outcrops of marl (a pale limestone mud sometimes used by farmers to `lime' their fields) and mayfly utilise this habitat to their considerable advantage. Caithness, Sutherland, Ross-shire and Argyll all have marl and mayfly present, so appearances can be very deceptive. It's also interesting that while mayfly habitat degradation is widespread in the south of England, huge numbers of mayfly continue to hatch unabated in the more pristine north .

Another oft quoted myth concerns the length of the mayfly hatch. Frequent mention is made of the `Duffers Fortnight' which occurs during May in southern England. In this short, intense hatching period, millions of mayfly emerge from nymph stage to spread their wings, drift on currents, dance airborne, mate, lay eggs and fall as spent spinners. Trout have a wonderfully excessive time gobbling up all stages of the insect and their normally cautious bent correspondingly diminishes. Anglers then rush to reap the benefits of this, their quarries reckless behaviour, and some splendid catches can result.

However it's always struck me that two or three weeks ain't really a lot of time in a six month fishing season. Luckily the problem can be rectified if you are willing to travel. Mayfly hatches are longer in Ireland and they last two to two and a half months in the highlands of Scotland. The bulk of the hatch may not happen until June in northern climes but it will then build to a crescendo by mid July and continue until mid August before finally tailing off. This period allows splendid sport to be spaced out through the season instead of having to cram it all into a short window of opportunity.

Once you've located your hatch there is still the tricky point to consider of how best to represent the mayfly. If you are of the limpid chalkstream club you will probably insist on a realistic dry fly imitation like the Grey Wulff, Grey Duster, Green Mayfly or maybe a Green Champion. If you are less purist you can be just as effective with a French Partridge, Wickhams or a Straddle-bug, and in my neck of the woods big mayfly-seeking trout go mad for Golden Olive Bumble, Invicta and even Elk Hair Sedges.

Personally I think success is not so much due to what fly you select but how you fish it. While it's true the trout are eager to feed, clumsy presentation with the fly crashing down in a heap of nylon is never going to inspire. Even if your casting is delicate, rock solid nerves and good timing are called for especially when fishing the single dry fly. Many trout are lost when we over-anticipate the speed of the take. Big browns which are busily feeding on mayfly often make a slow, deliberate, porpoise-like rise over the fly and snatch it under the water surface. In this case it's easy to strike too fast and lose the fish. Equally anglers sometimes fail to observe that a big splashy rise (when the trout leaps from the water) can sometimes mean the trout already has the fly in its jaws. Too long a pause before striking this spectacular rise allows the trout to eject the suspicious piece of metal in its mouth. Astute judgement is critical in all of this but don't worry, we all get it wrong now and again!

If you have not already done so get out there and enjoy (foot and mouth willing!) some of the finest fishing of the season. Mayfly the stuff of dreams