Comparaduns: Mayfly Dry Fishing Flies

When mayfly are hatching, one of the most effective dry flies you can fish is a Comparadun. These patterns mimic ‘Emergers’: mayflies struggling to squeeze out of their pupa casing (or shuck), either in or just above the surface film. No longer able to swim but not yet able to fly, they are at their most vulnerable. Trout are attuned to Baetis, Callibaetis and other seasonal mayfly hatches

Baetis & Callibaetis: an explanation

The terms Callibaetis or Baetis are often used interchangeably to mean ‘mayfly’, and that’s not wrong, in a sense. But, to be more accurate:

Mayflies (or Ephemeroptera) are the order;
within that order, there is a family called Baetidae;
within that family, Baetis is one genus (or sub-group) and Callibaetis is another.

Most of the thousand or so different species in the Baetidae family are particularly small, hence the common names ‘small mayflies’ and ‘small minnow mayflies’. It is the Baetis genus that nearly all anglers will be familiar with by their common name: Blue Winged Olives. Callibaetis are a far smaller genus in terms of known species (only thirty odd, compared to around one hundred and fifty Baetis) but still make up a significant amount of mayfly numbers.

Comparaduns: what they are, when and how to fish them

The Comparadun style of pattern evolved in the late 60s / early 70s and is primarily associated with Doug Swisher and Carl Richards. They argued that, when fishing a hatch and imitating Duns (emerging adults), the appearance and position of the body of a fly pattern was more important than the wing or the tail. This was considered a revolutionary concept at the time, but their ideas were proved to be sound.

As you’d expect from the name, Mayfly predominantly hatch in the Summer months. However, depending on location, there can be hatches from April (or even earlier) through to October (or even a little later). Because of the ‘low-riding’ nature of Comparaduns, these patterns tend to work best in calmer waters. Hatches tend to happen from morning through to midday / lunchtime.