Other Common Names: Speckle-winged quill
Scientific Names: genus Callibaetis

This swimming mayfly is the dominant mayfly in lakes. It can also occur in slow sections of some rivers. Hatches begin as early as April or May and continue until the end of September or early October.

When the water is warm enough, eggs grow to mature nymphs in about six weeks. This means there are several generations within one fishing season. The insects get progressively smaller with each generation; in spring, duns are usually matched with a size 14 dry fly, but by fall, a size 16 or even 18 is needed. Also, the duns get darker as the season progresses.

Hatches usually start in mid-morning or early afternoon. While trout take the duns during the hatch, they also take the nymphs beginning a few hours before the onset, and continue taking them during and after the hatch. A Pheasant Tail is a passable imitation of a Callibaetis nymph, but in my experience the Flashback Pheasant Tail outfishes a plain Pheasant Tail by three to one.

When fishing nymphs, use an intermediate line, a long leader, and an excruciatingly slow, steady retrieve. When using a dry fly, trim the hackle off the bottom so it is flush with the dubbing. A cripple pattern is usually a better choice when trout are feeding on the surface. When the wind blows, however, it an be difficult to get a drag-free float of a cripple or dun imitation, so you might want to switch to a nymph when it's breezy.

Spinners can be important. There are no tricks to fishing the spinner fall: just chuck your imitation out there with a thin, long tippet and wait for something to turn up; try to stay awake.


How to Match a Callibaetis

Hatches are matched from Westfly's database of "standard" fly patterns.

Size 14-16 Pheasant Tail. Gray to tan
Size 14-16 Quigley Cripple, Film Critic, Hackle Stacker. Gray to tan
Lakes, slow water: chuck-and-sit
Size 14-16 Sparkle Dun, Hairwing Dun. Gray
Lakes, slow water: chuck-and-sit
Size 14-16 Adams. Gray to tan
Lakes, slow water: chuck-and-sit
Size 14-16 Comparadun. Tan to brown
Lakes, slow water: chuck-and-sit
Size 14-16 Rusty Spinner. Tan to brown
Lakes, slow water: chuck-and-sit


NYMPH COLOR: Tans, olive-browns, olives

DUN SIZE: 6-12 mm (1/4-1/2 in)

DUN COLOR: Wings--mottled brown. Body--Brown-olive to gray on top, light tan to olive below

SPINNER SIZE: 6-12 mm (1/4-1/2 in)

SPINNER COLOR: Wings--clear or with occasional dark markings. Body--medium or dark brown or gray on top, lighter shade below

OTHER CHARACTERISTICS: Nymph--slender shape; gills have lots of lines in them; three fringed tails; antennae 2-3 times as wide as head. Dun and spinner--two tails.