How to Fish the Hendrickson Hatch

April 29, 2025 By: Phil Monahan

This wild brown trout fell for a CDC Hendrickson pattern on a spring afternoon. Photo: Eric Rickstad

“Found one!” Eric shouted from downstream. I hustled along the bank, making sure to stay well away from the water’s edge, until I reached his position. Crouching next to a bankside willow, he pointed to a spot near the opposite bank, where a stick protruding above the surface created a small seam.

“Watch just downstream,” he whispered.

Sure enough, a subtle rise that left a few small bubbles revealed a trout eating insects off the surface.

“Cool,” I said. “Go get him.”

“Nope,” he responded. “Your turn.”

We’d already “head-hunting” on the Battenkill for a couple hours, looking for fish, like this one, feeding on a sparse hatch of Hendrickson duns. We hadn’t landed one yet, but since Eric had cast to the previous riser, I was up.

I took a second to check my tippet for nicks or knots and blew on my pink-bodied CDC Comparadun to dry it and fluff the wing. The presentation was tough because I had to cast across the main current into slower water, and then drift close to the stick without hooking it. On my third try, I got it right, and a few feet below the stick, the fly disappeared. I set the hook, applied side pressure to lead the trout away from the wood, and after a short fight, Eric performed a textbook scoop with the net.

It was a gorgeous wild brown trout, perhaps 17 inches long, with a signature red tinge on the adipose fin. It wasn’t a monster—the river holds browns over 25 inches—but any dry-fly trout on the Battenkill is cause for celebration. We snapped a couple photos, held the trout in the water facing upstream to revive it, and watched it swim away.

The female Hendrickson dun is lighter and larger than the male, and the trout will often key on one or the other. Photo: Ted Fauceglia

The First Big Bugs

For anglers east of the Mississippi, the Hendrickson (Ephemerella subvaria) is among the more anticipated hatches of the year because it’s often the first major emergence of spring. Since they’re good-size insects—ranging from sizes 10 to 16—they draw even large trout to the surface, as well. In their book Hatches II, Al Caucci and Bob Nastasi call the Hendrickson “truly the exalted king of the early season,” and Theodore Gordon, the Father of American Fly Fishing, tied some of the earliest dry-fly imitations in the early 20th century.

Although an early afternoon emergence of Hendrickson duns is a great time to be on the water, many anglers find the subsequent spinnerfall at dusk to be more productive and the best chance to catch a trophy trout on a dry fly in spring. There’s nothing like scanning the water in the fading light and seeing a massive set of jaws close around a floating Hendrickson spinner. Racing against darkness, you’ll need your A-game to make the most of the opportunity by making a stealthy approach and dead-drifting a spinner pattern right in the trout’s feeding lane.

Important Stages

Hendrickson nymphs are classified as crawlers, which means that they spend most of their time hiding in and crawling among stream-bottom rocks and debris. With a robust body structure and three distinctive tails, they are fairly easy to identify. Because they move about to feed, they are occasionally dislodged and washed into the drift where they are available to trout.

Hendrickson nymphs have the thick body of a crawler, and three distinct tails. Photo: Carrie Seltzer (CC BY-NC).

As spring approaches—early as mid-March—the nymphs become increasingly active, triggered by increasing water temperatures and changing light conditions. When water temperatures reach the low 50s, the first hatches begin, with most hatches occurring when the water is between 52 and 55 degrees. The nymphs swim to the surface, shed their nymphal shucks, and emerge as duns. Because these new winged insects must drift on the surface until their wings dry and fully expand, the duns are prime targets for feeding trout.

Male and female Hendrickson duns look quite different, although they both have three long tails. In general, the females are cream-colored or gray with a pink tinge and are often referred to as “light Hendricksons,” while the males, called “dark Hendricksons” or “red quills,” are more reddish brown. These colors can vary from region to region and even between watersheds, and trout will often focus on one sex or the other during a hatch. Carry imitations of both in sizes 12 and 14.

After about 24 hours, the duns molt into spinners. As the sun sets, the males swarm over water, “bouncing” up and down in the air, and then the females join them. After mating, females drop to the water to deposit their eggs, followed by the males. This offers trout a chance to feed on big bugs in low light, which is why larger, warier trout prefer spinners to duns.

The male Hendrickson dun is called the “Dark Hendrickson” for good reason. Photo: Ted Fauceglia

Timing the Rise and Fall

The Hendrickson hatch begins in early April in southern Pennsylvania’s trout streams, peaks in mid-May in the Catskills, and can extend into late May or early June in northern areas, like Michigan’s Upper Peninsula. Overall, May is the most common time to catch fish on Hendricksons, except in the southern part of their range.

The daily emergence of Hendricksons follows a predictable but variable schedule. In cooler spring conditions, the primary hatch typically begins around 1:00 or 2:00 p.m. and can last for a couple of hours. Overcast days may see more sporadic activity, with hatches potentially occurring from late morning through the afternoon, depending on air temperatures. Unseasonably cold temperatures can compress the hatch, with more bugs on the water at once, making the helpless duns particularly vulnerable to feeding fish.

Spinnerfalls usually occur at dusk over stream riffles and faster-water sections. However, on particularly warm days, spinners may also appear in the morning, adding an unexpected dimension to the fishing day.

Keep in mind that spinnerfalls are often short, lasting 30 minutes or so. This leads to intense feeding periods where trout become highly active, but it can also shut off abruptly. The timing can vary slightly based on local conditions, with some regions experiencing more prolonged or multiple spinner fall events.

Hendrickson spinners usually fall to the water right at dusk. Photo: Carrie Seltzer (CC BY-NC).

Matching the Hatch

Choosing flies to match Hendrickson nymphs can be as simple or as complicated as you want it to be. Hare’s-Ear Nymphs and Pheasant-Tail Nymphs in sizes 12 through 16 will get the job done in most places, but there are also lots of more imitative patterns available. Before the hatch begins, the nymphs become more active and their wing cases turn dark. This is a great time to dead-drift a nymph, but if you’re not getting any strikes, try adding very subtle wiggles to your presentation.

As the hatch begins, fishing wet flies, CDC-wing emergers, and Soft Hackles is a great way to imitate nymphs swimming to the surface. Even when the duns appear on the surface, continue fishing these wet patterns until you see a trout rise.

Given the significant differences between male and female Hendricksons, carry patterns that accurately represent both sexes. The classic male Hendrickson dun pattern is the Red Quill, which imitates the smaller, dark reddish-brown males. For the larger females, the Light Hendrickson in gray-brown with subtle pink undertones is essential. Both patterns should be carried in sizes 10 through 14 to account for regional size variations. A double-dry tandem rig featuring one pattern for each sex will help you identify which the trout are feeding on.

On slower water, try Parachute patterns, Comparaduns and Sparkle Duns in sizes 12 and 14. These flies sit low in the water and present a lifelike silhouette. In faster water, switch to hackled flies, which will stay afloat longer when being battered by waves.

For the spinnerfall, the only fly you need is a Rusty Spinner in sizes 10 through 14, but it pays to tie the pattern in several variations. Most females drop their eggs from high above the water, but some fall to the water before releasing eggs. This means that trout might be selective to spinners with various wing positions—upright, half-spent, or fully spent. Spinner flies that feature bright egg-laden abdomens might make the difference during selective-feeding periods. For the evening spinner falls, a Rusty Spinner pattern in sizes 12 or 14 is particularly effective.

Strategies for Success

Fishing the Hendrickson hatch requires patience, observation, and adaptability. The nymphs are particularly active in the hours leading up to the hatch, so if you expect a hatch at 1:00, start fishing nymphs in the morning. Start by dead-drifting the nymphs, but as you get closer to hatch time, a Leisenring Lift can trigger strikes from trout getting ready for the emergence they know is coming.

Geoff Grant of Orvis hooked this beautiful Hendrickson-eating brown on a Parachute Adams. Photo by Phil Monahan

Once you see your first dun, it’s time to start imitating the emerging Hendricksons, which swim up from the bottom to the surface film. This is when wet flies and Soft Hackles shine, and you can either dead-drift them or let them sink and swing them through the current downstream. As you start to see more duns but before you’ve got rising fish to target, try an emerger pattern in the surface film.

When there’s a critical mass of duns, tie on a dry fly and go head-hunting. On many rivers—such as my home water, the Battenkill—blind-casting isn’t very productive. It’s better to find a specific rising fish to target. Then, it’s important that you don’t start flailing away at it immediately. Take the time to observe the trout’s feeding cadence, pick the best spot from which you can achieve a good presentation, and make your first cast count. Because Hendricksons rarely emerge in “blanket hatches,” trout eating them remain wary. I’ve put down more big trout than I’ve caught over the years, so wade carefully and make delicate casts.

Once the trout stop rising to the duns, take a break. Mostly likely, you’ve got several hours before the spinners appear in clouds over the water. (Although it’s worth mentioning that sometimes they don’t show up at all, which can be frustrating.) It’s best to wade into position before the spinners start falling to the surface, so you don’t throw a wake that spooks the trout in flat water. Again, delicate casts and good dead drifts are vital to success.

The Hendrickson hatch represents more than a fishing opportunity: it’s a celebration of spring’s renewal and a chance to throw big dry flies for the first time. For fly fishers, it’s a cherished annual ritual that reconnects us with nature’s most intricate rhythms, reminding us why we love trout and the rivers they inhabit.