Mayflies are not just in May

When mayflies start to hatch, trout go on the feed and for good reason; mayflies are high in calories which makes for a tasty snack.  These insects are found in pure, clean water and when you find them hatching in the stream, a river or lake you know you’re fishing in a good place. Here are a few others things about them to know to help improve your fishing.

One of the interesting things about the mayfly is that they don’t just hatch in May.  They might have gotten that name because a significant number of them appear when the water temperatures are on the rise in May.  That said, there are plenty of mayflies that hatch in the summer, in the fall, and in the winter.

These bugs will spend the majority of their life in a stage called a nymph. Some live in the silt of a pool, others cling to the rocks of a riffle, and still others spend their year in a run. Bounce some nymphs on the bottom and you’re likely to hookup.

When the time is right, the nymph swims to the surface.  In doing so they are extremely vulnerable to fish.  If you see the flash of a trout in the middle of the water column the trout are feasting on the nymphs swimming to the surface.  Try a Leisenring Lift.  Cast upstream and throw some slack in your line to get your fly to sink towards the bottom.  Before your line comes tight, drop your rod tip towards the surface.  When your fly line swings down below you, raise the tip of your fly rod.  The tension swings your fly from the bottom of the river to the surface and imitates the nymph swimming upwards.  It’s a great way to imitate the fly’s natural movement.

Mayflies use the water’s surface tension to break through their shuck.  At that point they are called emergers. When you see trout just under the surface or with their nose in the film, tie an emerger fly on your tippet.

Once the mayflies have pulled free of the shuck they’ll inflate their wings and drift downstream.  It takes them a dozen or more seconds to dry them off.  While they’re drifting, trout daintily sip them, and their rhythmic rise forms a distinctive ring on the water. Try imitating if possible.

A few days later the mayflies crawl out of their skin (literally) and mate. Then they have a rust-colored or yellowish-green colored body and transparent wings.  A few days later the females return to the water to deposit their eggs.  Then, in an interesting death march, both male and female mayflies hover above the water and then drop to the surface and die.  Trout love these insects when they make what is known as a spinner fall, and there are rises everywhere.

The study of insects is called entomology, and it can be very complex. To keep it simple, match your fly to the insect with this three-step process: size, color, and silhouette.

You Might Also Like

Tom Keer

Tom Keer

Tom Keer is an award-winning writer who lives on Cape Cod, Massachusetts.  He is a columnist for the Upland Almanac, a Contributing Writer for Covey Rise magazine, a Contributing Editor for both Fly Rod and Reel and Fly Fish America, and a blogger for the Recreational Boating and Fishing Foundation’s Take Me Fishing program.  Keer writes regularly for over a dozen outdoor magazines on topics related to fishing, hunting, boating, and other outdoor pursuits.  When they are not fishing, Keer and his family hunt upland birds over their three English setters.  His first book, a Fly Fishers Guide to the New England Coast was released in January 2011.  Visit him at or at