Whilst spring might be recognised as the prime flight time for Blacks Gnats, with several species occurring in this Bibio family, chances are they’ll always be an odd one about during the season. One terrestrial species in particular makes a resurgence come late August and September. As to the exact species and or whether there are actually fever flies (a close relation) matters little.
Black gnats, or Fever flies… I don’t think the trout care one jot!
Far more important is these late season falls tend to be on a Biblical scale, often summoning trout out of hiding for long periods.
In prime condition, this beauty fell for a drop arse gnat in late August
What’s more, being a terrestrial and after emerging from grassy meadows, black gnats tend to be consistent in their movements. Remaining on the menu day after day this then gives us plenty of breathing space to set out our stall when we can return time and again to experience a feeding frenzy of trout. Best of all, it’s all surface sport, so no need to panic if the nymph box gets left behind.
Equating to a about a size 16 hook, when naturals initially tumble to water it seems like fish are hell bent on getting their fill. Often now, we are able to throw a much wider range of imitations at trout. Dressings like the Black Hopper or a Target Beetle will come to the fore. Granted these patterns may be larger than most naturals, but often this works in our favour as it makes them stand out, especially when gnats carpet the surface.
Furthermore, whilst we’re taught to land flies like thistledown, it’s worth making them crash down occasionally. This act might seem sacrilege to seasoned dry fly rods, yet it has a habit of turning the heads of trout that often come dashing over to engulf a fly without a second glance. I hasten to add this tends to be a last resort after first trying a more delicate presentation on rising fish.
So far, I’ve painted a pretty picture of roses round the door when trout seemingly fling themselves at all and sundry. However, following the initial carnival, trout wise up to the idea that swamped gnats make a far easier meal. Ignoring high riding insects they pick out those partially drowned flies instead.
Naturals sitting in rather than on the surface soon
To get on their terms now we need something that sits in, or marginally below the surface. In such circumstances the Drop Arse Gnat, has worth and although not strictly a terrestrial, something like a Black Mirage Butt Cul or a Black Klink, can come in handy too.
Naturally, the faster parts of a stream will be an instant draw to anglers though rather than plumb for these, make a point of scoping out slower water.
Smoother water well away from the pool head is best when targeting terrestrial feeding trout
Here, more sedate flows see terrestrials loiter for longer making easy pickings for fish. Pool tails in particular often attract the better fish though here tricky currents can make for challenging presentation.
Oily flows see gnats gather in numbers
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