Following the BWO

However, I was there that year, for the late-in-the-evening extravaganza, the appearance of the Blue Winged Olive fall. And thus, there to realise, that although the Anglers Books and the Fishing journals and Fly tying gurus build these insects up to mythical status with countless patterns for this “incredible day time hatch”. This doesn’t cover us on the Willowbrook, fishing when we do, our world doesn’t work like that and most of those patterns are unnecessary.

Those Books tell us they hatch out from the stream during the day light with they’re milky blue grey wings, greenish olive bodies, and dark green eyes. Of all our Willowbrook’s smaller ‘Olives’,  all have two tails, this species is distinct with three, and easy to distinguish, even in flight . They pop up on the surface of the water, drift a little, drying those wings, held high like little Spinnaker sails and come bobbing down the current, mostly ignored, before rising safely away to the shelter under the boughs and branches of nearby trees and shrubs. In truth though, I’ve rarely seen this, despite my countless hours on the Brook.

These flies overwinter as eggs and then grow through several stages of lengthening (instars) through to July. We see them starting to become obvious in the kick samples of nymphs in late spring, and then the hatching adults appear through the surface in early July. A single fly emerging from the water or an optimistic couple have appeared and drifted down in the daytimes when I have been fishing, and have then waited eagerly for the main event. Hoping that, “this is the year at last that I am there just at the right moment”; but it has never occurred for me.

Yet on the nights I’ve seen the females coming back to the waters to lay their eggs, it’s obviously been a humungous hatch that has happens at some point. I suspect on the Willowbrook it’s a night time hatch, and the spider web visitor books along the bankside seem to confirm that theory, as quite a few don’t avoid these sticky traps spread within the Reeds or lower branches of the trees, when flying past the night before, and the next day they are still there struggling hopelessly.

I’ve tried to have sympathy for these poor souls, to be on their side, and to free a few up in the past from their confinement, as they are obviously very much alive still; full of potential, and grant them the freedom of the breeze. But those fine sticky threads are always stronger than the delicate wings and legs, and are conceived to wrap tighter, more secure with each struggling movement. I’ve never successfully released anything. The spiders always beat me and I just end up ruining an exquisitely beautiful web in the process.  Ruining the chances for both the spider and the fly.. Sometimes it’s best to resist being part of the narrative and not meddle with nature.

These BWO’s  (Blue Winged Olives) along with the Mayfly numbers, open up another question about perceived fishing wisdom and about mysteriously ‘missing’ hatches.

When we kick-sample for insects, our Mayflies and BWO’s when there at all; are usually in the 1-10 numbers present. There are rarely more than 10 in a sample, even just before the main hatch occurs. Whereas the other Olives ( up-wing flies) in the same sample trays are in their many hundreds and sometimes thousands present.

Let’s say there’s 100 times more of the Olive nymphs in the kick samples than a BWO or Mayfly nymph. ( ….and that really is a conservative estimation).

The numbers of insects in the BWO’s spinner fall and in the Mayfly’s hatch and dancing, in what we evidently witness,  occur in what  appear as ‘Biblical’ numbers. So, where are all these other Olives, that outnumber them a hundred to one?

At various periods of the day we’ll get an hour or so of a steady but by no means spectacular smattering of Large dark Olives, and occasional small hatches of other species that never amount to much.

The Small Dark Olives, the Medium Olives, and the Iron blues, confuse these numbers even further. We get two generations during the year, the over winter and then the late summer. They do appear in hatches in drips and drabs late afternoon, and are some of the early evening flies. We very occasionally see clouds of males dancing, but the females going back to lay their eggs are rarely witnessed?

The females of these species land on stones or semi emerged branches and climb down back under the surface to lay their eggs, rather than the typical laying prostrate on the surface.  Then they attempt climb back out and many are swept away traveling downstream to meet the food lanes, but we just don’t see the numbers or the big hatches or the egg laying ‘falls’, that kick-samples say we should. Unless they are just a slow steady drip throughout the season rather than the flood of activity that come with the Grannoms, Mayflys, and BWO’s. The breeding cycles however, don’t seem to support that.

The Iron Blue males (known bizarrely as Jenny Spinners) at the time I was writing about, did congregate in some dense little clouds,  dancing along the banksides, late at dusk, their large bright orange eyes and pale bodies  an easy give away for an enthusiastic nerd trying to devour knowledge and identify and label that wonderful world around him. Now we don’t seem to see the Jenny Spinners at Willowbrook for some reason. That dancing movement in the clouds I suspect could be the source of the name, not a female Jenny, but the Spinning Jenny and early industrialised spinning loom. But don’t quote me on that!

This display however at the brook, was not in the afternoon as many books say. I only saw it in the evenings as they displayed  for the  females who then go and find a suitable place to crawl under the surface and lay eggs. So, I suspect here, lots of activity went on after dark. The hatches of this species was said to be in storms and therefore not seen by the angler, I wonder if it was after dark too, but didn’t sit with the traditional wisdom of “morning sessions”, “afternoon -hatches,” and “Evening- rises”, being the parameters of our arena and of the life within it.

I think some of these missing numbers can be down to predation on the stream bed, it is after all a jungle down there with some ferocious monsters, but surely not that huge percentage lost. I am getting more sure the hatches occur when we fly fishermen are not around, nor are the song birds’ or any of those summer migrant insect eating birds, that visit Britain to raise clutches of fat chicks on grubs and insects.  Safety-in-numbers-hatching in the dark, It’s not so much finding a smoking gun, but slowly uncovering a collection of clues that leads me to that assumption and change my fishing habits.

Those BWO lady’s in flight pass you slowly, just avoiding  you in what seems the enormous effort to change course. Not taking a wide cautious berth of you like some of its brethren do. You cannot mistake these females, the onerous flight, looking like little hockey sticks weighed down, fluttering past. The egg balls held at the back tilting them down and creating this appearance. If you could hear them they would probably sound like the dull deep drone of an overburdened Hercules transporter plane .

First you see ones or twos and they register with you. Then within a few short minutes you find yourself surrounded, it just switches on. That evening of the season that they first appeared in the year of not stocking, I tried to work out where they were heading to lay the eggs.

From those ‘learned’ books written by fonts of wisdom; by those scribes who have mastered Fly Fishing, know absolutely everything there is to know, and then generously share this wealth of knowledge with us plebs; Either published in something like Bullshit press for £18.95 or printed monthly on the news stand for £4.95. These informed me usefully; “BWO’s always move up-stream to lay their eggs” and “ in an area with Ranunculus weed”.

The air was quite thick with them both upstream and downstream of me. But, they were all heading ‘down-stream’ past me. The Willowbrook Blue Winged Olives hadn’t read “My Years of Fiddling with my Rod” by Rollop Wallop, or subscribed to My Bulging Box Fly Tying Magazine it seems.

I pulled out of the water and scrambled up, to look down on them from the high banks above the Groynes, “Wherever those spinners were laying there eggs the Trout would be having a fiesta down-stream”……or so I thought.

From the new vantage point I could see the extent of this phenomenon. The moving block of egg laden females wasn’t  just a few feet over the water as it appeared from in the stream, it stacked up in a column 20 or 30 feet above me, and from where I was stood on the bank above the Groynes beat, I could see them trailing all the way to the distant Packhorse bridge, and I set of downstream to follow them.

As I reached the bridge, they continued down to the tree lined part of the Brook. I followed them through the trees and they continued onwards. I followed them over the open water by the wooden footbridge where the column was fully evident again. I followed them back into the trees and continued downstream, and then they seemed to disappear from view. I backed up stream searching.

That’s when I came to a small clearing in the canopy where the last light of the sky was reflected,  glistening on a patch of broken surface of a shallow riffle, distinct from the now gloomy shaded water surface under the canopy both upstream and down of here. They had passed over countless thick Ranunculus beds to get here, but there was none in this area.

The females were here, many were landing or skimming close to the surface dropping the egg balls in small effort that twisted and contorted their slender bodies, and free of this last act of life,  they dropped to the surface and they drifted, still contorted down- stream.

I didn’t see, but I did hear a few fish down-stream taking advantage of this. There was no expected fiesta that I witnessed. I did look at a few of the bodies floating in the glossy water of the relatively still and quiet margins, away from the main current, prompted by one of Stuart Crofts visits and his pattern for this fly.

None looked like the typical straight neat bushy size14-16 sherry spinner as a typical pattern in the books with dense red Cockrel hackles, prostrate white wings, bodies of orange or claret silk ribbed in gold tinsel and then three immaculately spread single filberts for tales. Some of these, that seem to me, ridiculously overdressed pattens even include the egg ball which will already have been shed by the time the Trout encounter this stage of lifecycle.

A typical commercial sherry spinner pattern

Those actual real flies on the surface, ‘spent’, what was left of them, were just wastrels for a size 16-18 hook. They look ‘shagged-out’ after a hard short life, which is exactly what they were. Dull, lifeless, bent or twisted bodies and two spread lifeless wings, so simple, just glistening in the golden late light.  The surface in that small respite water, in the gloom, resembled a little, the preserved aftermath of Pompeii, full of contorted shapes, their last struggle frozen in time, before at last drifting away downstream in the last light of sunset….  Very few Trout, if any were taking advantage of this feast, at least while I was there to witness.

Cranked sherry spinner pattern loosely based on Stuart Crofts pattern

I hear on other rivers that these BWO spinner falls happen quite regularly late into the season over quite a period of time, and often earlier in the evening. On Willow brook it seems we get a couple of nights of concentrated activity over a week.

One year I’d been lower down stream of this spot when they suddenly occurred, and I came across ancient instincts colliding with this modern world.  They again were heading down stream, I followed them back and could see them lifting to pass over the Apethorpe road bridge rather than passing under it.  It had rained heavily earlier but the water hadn’t responded with a rise in levels yet, and there was a side breeze that they were battling as the treeline ceased to shelter them, nudging the cloud off to the side, away from the water at times.

As I clambered over the gate to follow them downstream there were two puddles on the tarmac either side of the bridge glistening in the light pouring down from the broken canopy above, the breeze breaking the surface. Hundreds and thousands of these poor females were cruelly fooled into wasting their life’s chore on the surface of the downwind puddle. On that tarmac road appearing for some reason, like a patch of prime BWO river bed in that gloom, an entire generation was wasted.

At home I looked back at old journals from when I had first joined the Brook. I’d write down observation of each trip as I was enthusiastically at last learning to fly fish in moving waters, one of my life’s ambitions;  noting  everything I thought relevant. The flies used; the various lengths of nylon I’d put together to try and find a leader combination that actually worked, all the fly’s I’d tried that night. The fish caught, their weight; length; and crucially, with each, the stomach contents.

And on the day of July 13th,  when I drew a new fly I seen that night, with an egg ball under its tail in the margins of the page. My first known encounter with a BWO. I caught one fish that night  of 1lb exactly on a “size 16 PT dry”  (whatever fly that was?!), and the stomach contents were written up thus:-

“BEETLES!! All sizes from a few mm to 1cm round, and elongated. Black, Sailor beetles; striped beetles; Round ones; thin ones, long ones; teeny weeny ones; So many different types of Beetles in one little Tummy, oh and a few squashed olives!”

Pic; My old journal page from when I first started

As an entomological record it was of very little value, but as a window into the feeding habits of the Trout, that I caught, accepting that other fish in the same Brook may have been feasting on other morsels with differing feeding habits, and that most, but certainly not all, that I was catching at the time, where stocked fish. This list of ingredients over the season was mostly a wide variety of Beetles and black flies, and it should have been priceless knowledge.

This diet that I logged over the year, also included a few things that I regularly saw by the water, but, that some wisdom from an older member , or an article read, had dismissed and declared that the Trout never actually ate. Those black and orange Sailor beetles, the brown and orange soldier beetle, and the caddis looking Alder flies; were all said to be avoided. Not by our Trout however, they loved them and ate them in numbers according to my grizzly autopsy’s enroute to the backyard Smoker.  

They also ate  a wide variety of things, little black flies, reed smuts; mosquitos; larger black flies; colourful dung flies; little greenfly aphids; huge crane flies ( daddy long legs); hatching caddis flies; winged caddis flies; Wings with no flies attached at all ; pollen beetles; flower petals; entire hawthorn flowers; grass seeds; bud covers from developing shoots off the trees; (including some really big sticky bright magenta Horse Chestnut buds); Hawthorn berries, empty snail shells and tiny muscle shells were all noted in my journal. Some bizarrely,  just like “normal Trout” in the text books and magazines do, also ate the odd Mayfly and Olive, but also a rolled up ball of gold paper from a fag packet and various bits of coloured plastic were found. Try matching the hatch to that eclectic mix.

Very few caught seemed to have been eating nymphs, shrimp or small fish. These fish had typically been caught under the foot or so wide trail of bubbles and scum that winds its way down stream, where all the surface debris is concentrated, that we christen the food lane, and our feeding Trout, those that I caught, would sit under it or by it, observing whatever was conveyed above them and quite obviously eat anything that came downstream behaving like natural food stuff.

That simply put, I feel, on Willowbrook and many rivers, is what is needed to fool them and what should be concentrated upon, “behaving like a natural food stuff”.

What is incredible to me, years later, reading this notebook back, was that I still had dedicated years to slavishly matching the hatch with the various life stages and genders of a limited number of species that we were encouraged to fill our boxes with. Halford and co’s old spell was a hard one to break it seems.

In the light of all this simple gathered evidence, I still preferred to side with these romantic or nostalgic notions written down in the books and magazines, that dry fly fishing for trout on streams , was about careful imitations  of predominantly ‘Up-wing’  (olives) and of caddis flies.. And that it took fly tying entropy, a slowly disintegrating example of my terrible fly-tying, to shake me out of this foolishness and wake up.

My stupidity with hindsight, never fails to amaze me. Apart from beetles, the things I saw in flight over the water by far the most was various types of black flies, from reed smuts to dance flies, simuliidea and some parasitic wasp looking flies; and these all turned up in numbers in the stomach contents along with the occasional olive or stuck emerger. Yet my fly boxes were full of imitation olives and a few caddis.

Theres few times I’ve seen really switched on specie specific feeding on the Brook , but that’s not to say that if you presented something else in the same natural manner it wouldn’t  be snapped up.  The Grannoms, when so many of these things are on the wing in the daylight hours, its like a coach load of drunks descending on the fair ground dodgem cars, they crash and flutter on the surface and then kick up so much fuss. It seems they are magnetic to fish coming out of a sparse long  winter, and it is one of the few times you can truly appreciate just how many feeding fish the water holds. There seems to be Trout everywhere!

The other is the Mayfly, especially when they first start to hatch and these large flies are struggling in the surface or riding briefly while there wings dry. Even after liftoff when they seem safe, the Trout seem to learn young, to jump clear of the stream and hit them in the air, which always amazes me. The way the light is bent by the water surface, the refraction, they have to account for that and range find and predict the path. It’s rarely you see them miss, its usually a clean catch right down the middle!

But then a few weeks into the Mayfly and it changes. Those Mayfly are still around and on the Brooks surface, a regular stream of spinning females fluttering up disturbance on the water with their prostrate wings, shedding their eggs; and then, drifting down stream, spent, and twitching away the last of life.

I had set up a camera on a tripod determined to ‘nail’ the shot of a Trout opening up its cavernous maw in the surface film to consume one of these creatures, in an attempt to win a yearly RiverFly  Photography prize that I kept coming runner up in, and this year was determined to put in an effort for a change.

I found two reasonably good sized Trout on the feed, sat in station, one a few feet behind the other, under the food lane close by my bank, and I watched through the lens as the Mayflys drifted down, and like boxers reacting to jabs they dipped and dodged every Mayfly that came down their way, but then returned under the food lane and regularly slashed at, and hammered something so small that I couldn’t work out or see, through the viewfinder of the camera, and couldn’t time the shot.

I went down stream with a fine meshed drift net that I always carry, and held it in the food lane. There were tiny, say 4-5mm, Small Spur Winged Olives, these were what was hatching and drifting down. Now back through the lens, knowing what I was looking for I could see clearly the two trout Dodging 25mm-30mm bodies of Mayfly feast for the preferred tiny 5mm snack. Why?

Now my ‘sense’ is rarely common, and I’m as able to jump the gun and come to the wrong conclusion as ineffectively as any dunce and duffer.

But its seems as you get to know the world around that creatures have a inbuilt ability to target the most beneficial morsel. We hear of Orcas in South Africa hitting 19 Great White Sharks in a day, just eating their rich livers and leaving the carcasses to rot. It is written up that this selective feeding is in the realm of the upper orders of the animal kingdom.

However, there are three specialist ant eating spiders species, that only consume the specific parts of the ant with nutrients they require at the time, whether that be a shortage of lipids or proteins, but then when they require a different nutritional shortage they select other body parts of the ants to satisfy that particular need.

In Australia there are some insect eating Marsupial species that devour their prey  based on the priority of its nutritional value. For Beetles and cock roaches  they first eat the abdomen, then the thorax, head, and finally legs. For Centipedes it was body first, heads and finally legs. The selection of the body parts correlated closely with the energy densities of those regions and the rate of energy intake they yielded.

(This in no way relates to the habit of the young human; Chris Avery, who when given a jelly baby would always chew the head off first and then the feet and legs, and continues this behaviour into advanced adulthood… that is more of a deep psychological disorder and the therapy is ongoing)  

We see it on the river banks of the UK, Crofts has noted predatory Dung fly’s  consuming just the    “soft ‘good’ stuff” as he puts it in a broad Yorkshire accent, in the top of the thorax of caddis flies caught perched on a leaf. The heads sometimes fall off and they dump the abdomen and wings. As these traits are not learnt from paternal upbringing like maybe with the Orca or even marsupials, they must stem from something innate.

We humans romanticise about ancient hunter gathers and the aboriginal people of the world that waste nothing and utilise every last bit. But in nature, often the good is taken and the  wastage is left for the cleanup guys, the scavengers; the vultures; beetles; flies; fungus; and bacteria.

And so, you have a Trout faced with choice to gorge on the easy pickings of very large females, empty now of eggs and near the end of life,  a packet of skin and wings and legs. Lots of bulk to fill their bellies quickly  allowing  the feeding urge to be turned off and get them sooner to the safety of cover under the banks. Or, to stay out longer in the vulnerability of mid-stream selecting the much smaller morsels of freshly hatched fly, full of all the energy it has developed over the past 6 months and has stored up, for a few monumental days of changes and breeding. And the Trout selects, it seems, on the nutritional benefits to best benefit the egg development or condition to be selected for breeding.

That really is the only truly selective feeding I’ve ever witnessed on the Brook in many years, but,  had I dropped a Beetle pattern in front of those Trout… they’d have probably taken that too.