Fly Fishers' Republic

The Hawthorn Fly :
Bibio Bounty

April 25, 2006

by Andrew Petherick

Hawthorn fly (Bibio marci)

If you have fished before, and as you’re reading this I’ll assume you have, the chances are you’ve heard of the Bibio. This may be in its proper context, as a terrestrial fly, or you may have heard the name loosely used for a fly pattern. Used in its correct context, it is the Linnaean classification of a genus of flies. This includes hawthorn flies, heather flies, and the black gnat.

You can expect to see hawthorn flies flying around the countryside from around mid April onwards. The hatch usually lasts until the first week of May. I base this on the UK’s southern chalk streams; this will vary for different regions (I did once find one in a boat at Grafham, at the end of May; it was alive, but barely!). The hawthorn is a bit of an oddity to the fly angler because it is only by chance that it finds its way onto the water. The larvae mature underground, in burrows. They emerge at springtime, to find a mate, which is when they are brought to the angler’s attention.

Hawthorn Fly in flight

Conditions have to be just perfect to get them onto the water. You’ll know if they are about or not. During the times suggested, take a walk along the hedgerows during the afternoon, you will easily see the adult fly, normally in swarms, flitting about, trying to find a mate. They are instantly recognisable by the long, dangly legs they carry in the under carriage. They are quite therapeutic to watch, but frustrating to try and catch, and take a picture of!

To cash in on this hatch you need a few things in your favour. A warm day (more activity), a light breeze, and more importantly, a breeze that is blowing towards the water you are going to fish. Hawthorn flies don’t go near water by choice. Their bulky, awkward flying ability (or lack of it) means that they are easily knocked off course, and end up on the fishes’ menu.


An emotive area! If you fish for trout frequently, go to the next section, if you are unsure, please read on. Tackle choice is highly dependant on the water you are fishing. Chances are that you will have the correct rod already. Bearing in mind that the flies can be big and bulky (The natural is around 12-15mm in length) you will struggle with anything less that a 5-wt (more about the flies later).

As these flies are likely to appear on a number of water types, I have put what I would choose into a table format:

Water Type Rod
Small River 8ft 6in 5-wt
Medium River 9ft 5-wt
Large river 9ft – 9ft 6in 6-wt
Small still water 9ft 5-wt
Medium still water 9ft – 9ft 6in 6-wt
Large still water 9ft 6in – 10ft 7-wt (the longer option for boat work)

I would look for a rod with progressive action, middle to tip. This will enable you to form tight loops, to cast accurately to rising fish; it will also go a small way to protecting light tippets. The chances are that you already own a suitable rod. If I have an option, when fishing a hawthorn hatch (any dry fly hatch really) I will use a double taper line, instead of a weight forward. This is because the profile allows you to pick up longer lengths of line, really useful when you have to be as accurate as possible, as quickly as possible. Action can be sporadic; its best to make sure that you can get your artificial to where it needs to be, pronto!

Netting a fish

When the fishing is good, when there are lots of flies on the water, action can be thick and fast. Drying out your fly to convince the next fish is sometimes tricky. If you believe in floatant, fine, use it; I have to say that I am not convinced by it. Amadou is probably the best thing, but not everybody has access to the better quality stuff that performs as it should do. I would advise that you carry as many hawthorn flies (same or variations on a theme) as you can afford/tie the night before. It’s easier, in the heat of it, to tie on a new fly and leave the soaked fly to dry naturally on your fly patch. If you are really lucky, by the time you have worked your way through the dozen in your box, the first one will be dry. Clever anglers will treat their flies with Water Shed the night before (a great water repellent but it takes 12 hours to dry, so not an on the bank remedy) or source flies that are made of foam. The latter being the best option, more on that later!

Leader set up

Now, this is where I will demand that you get down your local tackle shop, and part with some of the cash you have been hoarding in the sock draw!

Tapered leaders. I will say it again, tapered leaders. Once you have used them, especially for dry fly work, you will never look back. Do not underestimate the power of these things to make you a better angler. A 9ft-tapered leader will make you more accurate, and give you better, more consistent turnover and presentation. If you are a confident caster, go to 12ft. For surface work choose nylon, or a co-polymer, these have the added bonus of inherently floating.

If you find fish are rising to your fly, and just boiling at it, or turning away, you can start to get a bit technical. You can degrease the tippet section next to the fly, about 12inches in front of the fly. I would recommend Orvis mud for this, not only does it sink your tippet, but it takes the shine off your leader. ‘Xink’ or the equivalent will do the job also. If you are stuck with your pants down, mud off the bank will do at a push.

If you want to go really techno a good tip is to add two feet of fluorocarbon to the tip of your leader. Fluorocarbon, due to its chemical make up has a specific gravity that is greater than water, basically, it sinks. (Use a sinkant as insurance though, in breaking strains of less that 4lb, it does struggle to break the meniscus of the water). Make sure that you use a proven knot to join the materials, like a four turn water knot, and that you trim down the tag ends of the knot to avoid tangles. Also ensure that you step down in diameter, or breaking strain to keep the turnover characteristics of the leader you have forked out for, i.e. if your leader has a tippet of 5lbs (about right), step down to 4lb tippet, even 3lb if takes are not forthcoming.

Why do you want your leader tippet to sink? Simple. When your fly is floating on the surface, the chances are that the leader is doing the same, just resting in the meniscus. A fish can see this a mile off, and will leave your fly alone. By ensuring that your tippet breaks the surface tension the leader will ‘disappear’. Obviously, if the whole leader sinks, it could/will pull the fly under. Sinking the tippet is the only viable option.


These are some of my tried and tested Fly Patterns:

Oliver Edwards Hawthorn

Rubber legged hawthorn

Hook: 10 – 14 Light wire
Thread: Black Uni 8/0
Body: Black, high-density foam
Legs: Round, black rubber
Wings: White polypropylene

Notes: This is my joint favourite. It floats forever, is durable, and fun to tie! If you don’t tie, you can get them from Orvis stores. Great for broken water at the heads of pools, or fishing New Zealand style, with a micro nymph, if action is slow. A truly excellent pattern, thanks Oli!

Traditional Hawthorn

Traditional hackled dry fly

Hook: 12 Light wire
Thread: Black Uni 8/0
Body: Black floss
Legs: Knotted black pheasant tail
Hackle: Black cock
Wings: White cock hackle tips

Notes: One of the more famous patterns. A true all rounder that will catch fish at all times of the year, it looks like a myriad of bugs and creepy crawlies. Worth having a few in your box.

Suspender Hawthorn

Foam suspender pattern

Hook: 10 – 12 Light wire grub hook
Thread: Black Uni 8/0
Body: Dubbed black antron
Rib: Flat pearl Mylar
Legs: Knotted black pheasant tail
Wings: White cock hackle tips
Head: Black plastazote

Notes: My other joint favourite. The perfect pattern on waters where you have a mass of flies, and the fish are not necessarily looking for ‘live flies’ on the surface. They do drown you know, but more on this a moment.


Stillwater (all types and sizes)

If you are lucky enough to be in the centre of some hawthorn action, make sure that you chuck something that resembles a hawthorn at them! Sounds funny, but people don’t change flies, I assure you! Cast at rising fish, if they are not spooked they will be cruising about just under the surface. Their cone of vision will be quite small, as they are close to the surface, make sure each cast counts. I prefer floating, preferably foam flies. These are great; you can cast them out, just take up the slack, and wait for that big back to roll over your offering. If you tie your own, make sure you make that wing nice and big so you can see it at range. As long as the rules permit, don’t be afraid to fish a team of three hawthorn patterns. But don’t put all your eggs in one basket – make them three different patterns and see which one the fish show a preference for. If they are constantly taking the same one, it doesn’t take the brains of an archbishop…

River (All types, chalk stream, freestone, small, medium, etc)

If you have a large amount of bank space, remain mobile; move about, DON’T GROW ROOTS! Go and look for the action. Hatches can be sporadic, go and look for some flies in the air. If the water is pressured, some fish will be reluctant to take off the surface, and will wait for submerged flies to drift past. Fish a foam, or highly buoyant fly, and drift a small nymph under the adult hawthorn. It goes without saying that you should cover rising fish, common sense really, just make sure that your leader is long enough, mud applied, and that you remain concealed. This is one of the first major hatches the fish will have seen this year, they’ll be spooky.

Netting a fish

River and Stillwater

Don’t be disheartened if you turn up at your venue (river or stillwater) and you find no fly life, and hear those immortal words, ‘you should have been here yesterday’ (always said by someone who lives on the water…). If there was a hatch that ended up on the water, this is good news! It means the fish will be receptive to the artificials; they have been conditioned, by the previous day, to look upwards for big black leggy things. Go for it!

And don’t forget to wiggle it! Yep, like I’ve said elsewhere, wiggle it! Think about it, an adult hawthorn lands on water, what’s it going to do? Do its damnest to escape the pull of the water tension, that’s what. It does this by wriggling like crazy, and beating its wings. This sends out a vibration, that a fish’s lateral line (what it uses to locate food) will home in on, and it will come and investigate. You can recreate this, at short range, by holding your rod at approx. 45° and wiggling the tip, this will send shock waves along the line, and impart life into your artificial. Standby for action!


Extra Kit: You don't really need any special extra kit for this kind of fishing. I would recommend that you take a set of packable waterproofs, common sense really. If you are really into your fly tying, I would suggest that you take along a 35mm film case. Try and capture an adult hawthorn, and do some imitating (Good luck catching one...)! I really like to use foam and rubber in my tying, you can get some really good effects. Have a look at Loco Foam from Veniards; Orvis do a special foam kit for this type of tying. If all else fails, try the foam from a mouse mat!

If you don't dress your own flies, see if your local fly shop can help. Otherwise they're available on-line from companies like Sportfish who distribute the Fulling Mill or Umpqua range.