In my article, Presentation under the microscope (FF&FT, December 2007), I stressed the importance of good presentation and said that I don’t believe in ‘magic’ flies, being of the opinion that in any given situation a range of similar flies will be equally effective.

However, I do believe our choice of fly should have the right ‘triggers’ in order to convince the fish it is food. These may be size, shape, colour, position on, or in, the water and movement, or a combination thereof.

In this article I’ll deal with colour. Colour has been shown to be a powerful trigger for a number of innate (in-built) vertebrate responses. Dutch ethologist and ornithologist, Niko Tinbergen, demonstrated that the red spot on an adult herring gull’s beak stimulated the chicks’ “pecking for food” response. He observed their strengthened response when a model beak with a bigger area of red was used. Konrad Lorenz noticed that male sticklebacks would attack anything red, even the image of a Post Office van seen through the glass of their tank, thinking it to be another male. Many fish appear to be “genetically wired” to respond to colours towards the red end of the spectrum. It is probable that the orange and red bellies of spawning brook trout and Arctic charr and red on the enlarged dorsal fins of male grayling are triggers for courtship responses.

How does this relate to the colour of our flies? Most aquatic invertebrates are well camouflaged, having cryptic colours of brown and olive, in order to avoid predators. The freshwater shrimp, Gammarus, is typical, being a drab olive-brown. However, there is a parasite, an Acanthocephalan (spiny headed worm) larva, which produces an orange cyst making infected shrimps more attractive to the fish (the secondary host of the parasite). Also, during the breeding season shrimps develop an orange tinge caused by carotenoid pigments, which also colours the flesh of trout which binge on shrimps. I have had great success with orange-spot shrimps tied using fluorescent orange beads and with shrimps tied using bright orange, spiky dubbing such as Standard SLF. My best ever grayling, 2lb 10oz, fell to a bright orange shrimp.

Serratella (Blue-winged Olive) nymphs often have a distinctly rusty/orange tint and grayling in particular seem to be suckers for small orange hare’s ear nymphs. The late Dick Walker noted that the colour of blue-winged olive duns was due to a blue exoskeleton covering an orange body. He used this to explain the success of the Orange Quill, a question which had confounded Skues. He believed that the fish were less sensitive to blue and therefore saw the fly with a more orange hue. Walker’s BWO Dun was tied with a mixture of blue and orange wool for the body. I must confess to being sceptical about the importance of colour in dry flies, believing that the fish nearly certainly see them as silhouettes.

View from below
In the 1950s Eric Horsfall Turner designed a tank in which to view dry flies from below. He noted that to the human eye colour was hardly discernible. At one time Walker’s BWO was my standard pattern, but now I mostly use a size 17 IOBO Humpy (see December 2007) as an emerging dun, or a CdC Gasparin Dun (my name for a fly which I believe to have been designed by Branko Gasparin of Slovenia). Nevertheless, I’m keeping an open mind on the subject of colour and dry flies, particularly those with submerged bodies, such as Klinkhåmers.

Other flies in which orange has been very successfully incorporated include Buzzer Pupae where the wing buds have an orange tinge: I’ve found buzzers with fluorescent orange beads for the whole head/thorax to be very effective. Then there is that old favourite of the spider fisherman, the Partridge & Orange, a fly which was never off my cast of two or three flies when I started fly fishing in the 1960s.

Pink has become a very popular colour recently. It was in the 1960s that Dick Walker mentioned pink with regard to shrimp patterns, which prompted me to experiment with patterns tied with a mix of hare’s ear and bright magenta synthetic wool (similar to Antron). Why should pink be so effective against trout and grayling when it seems to be absent in the aquatic environment? If you ever catch an American brook trout, have a close look at the tiny spots on its flanks: they are bright pink. They must be important to have evolved (probably species recognition).

There is no doubting the effectiveness of pink, particularly for grayling. I use Bugs and Shrimps from subtle to garish. I use them to great effect. Mike Weaver, in his book on wild trout, mentions the success of a pink Mayfly pattern. I often use a pink Glister Twinklehåmer, on which I caught loads of grayling on the 2007 Fly Fishing & Fly Tying trip to the Rajamaa Fish Camp, Sweden, with Magnus Angus.

Red has long been recognised for its appeal, witness the popularity of the Red Tag fished wet or dry. I have found bloodworm patterns in their various guises to be excellent not only for stillwater trout, but also in rivers for trout and grayling. When tying them, my main concern is to achieve the bright, translucent effect of the natural. With the use of Flexifloss Dick Walker’s Red Rubber Band fly has evolved into the Apps Bloodworm. Red holographic tinsel ribbed with red wire or red Flexifloss on a grub hook also works well. I add a black tungsten bead at the head if I want to achieve depth. For those with little tying skills, small red glass beads threaded and glued onto a grub hook make a first class imitation. Another favourite pattern of mine is a copper head nymph with a red wire abdomen and hare’s ear thorax.

Yellow is not a colour I often use, but when the Yellow Mays are emerging on free stone rivers I wouldn’t be without Oliver Edwards’ Yellowhamer. I also tie some of my sedge pupae in bright amber/yellow, whilst some of my Peeping Caddis have yellow bodies. Maybe I should experiment more with this colour since anato maggots were great catchers of coarse fish when I was a kid (before anato dye was found to be carcinogenic!) and sweet corn is the choice bait of many who trot for grayling in the winter (when it catches lots of out of season trout as well): not a natural bait, but devastatingly effective.

Green has its day. Rhyacophila larvae, some cased caddis larvae, some caddis pupae and damsel nymphs are often quite bright green. I like to exaggerate the brightness to increase their appeal. Some people like a green tag (egg sac) on their dry sedges, particularly Grannom.

Purple. Oliver Kite introduced purple thread into his classic Imperial to imitate olive duns. Jesper Larsson, the chief guide at Rajamaa, uses to great effect, a monstrous purple Klinkhåmer, the Purple Ugly (see article in previous FF&FT). The Snipe & Purple is a classic wet fly (probably imitating the Iron Blue), which I rarely had off my cast in the 1960s. I also have a purple Zonker given to me in Alaska by a guy fishing for rainbows: he described it as “the best rainbow fly ever!” I’ve only used it once since I rarely fish with lures, but it caught well then. Maybe I ought to experiment with purple?

Blue is another colour I’ve neglected. Fish are reputed to be less sensitive to this end of the spectrum and yet blue light, being shorter wavelength than red and higher energy, penetrated much deeper into the water. Davy Wotton has mentioned the effectiveness of tiny blue Buzzers in this magazine and the Teal, Blue & Silver was once a respected fly for both trout and sea trout.

Black … a complete lack of colour! I’m finding myself using black flies more and more. Success is largely due to the strong silhouette which black flies make against lighter backgrounds, particularly the sky. It has long been recognised that black flies are very effective for nocturnal sea trout, but two recent experiences have convinced me of their value in spate conditions. In such low light we want something the fish can see. My automatic response to highly coloured water was to increase the fly size and use bright pink Shrimps or gold head Nymphs with bright orange bodies. I’d catch a few fish, but never many. Last year during a spate, on Pickering Beck, I’d fished large bright flies for an hour with no success. In desperation I changed to my favourite nymph, a Black Bead Pheasant Tail in size 20. I immediately started catching both trout and grayling, ending with over 30 fish in a couple of hours. My second experience was also on Pickering Beck during a spate in May. I nearly returned home on seeing the water, but a single riser showed me that fish were feeding. It transpired that the gale, which was blowing branches off the trees, was also dislodging thousands of aphids. A size 26 black CdC IOBO Humpy accounted for 20 trout despite the water being the colour of milk chocolate.