A shift in the season brings more food options for trout, and more opportunities for anglers.
[by Aaron Jasper]
FOR MANY ANGLERS, the arrival of spring signals the beginning of the official fly-fishing season.The longer days combined with warmer weather coerce fishermen out the door and to the water to cure the onset of cabin fever, as it should; it’s a great time to be on the water.The temperatures are rising, the trees are sprouting green leaves, and the trout are ready to feed on the first great hatches of the year.
In the excitement to return to the water,the wide variety of conditions you could face, or any of the spring hatch stages you might encounter, are likely afterthoughts.
But by honing in on a few food items, you can make the jump into the new season less difficult than it needs to be. To help you enjoy a successful start, here is a brief look at six of spring’s most common aquatic insect hatches, how to effectively fish the most productive part of the bug’s life cycle, and some patterns the fish in your favorite waters likely haven’t seen.

(photo by Ted Fauceglia)
Blue-winged Olives
This spring blue-winged olive (Baetis) emergence is Mother Nature’s way of letting fly fishermen know warmer weather is on the way. This hatch takes place throughout the entire country, though the best hatches often occur on tailwaters, spring creeks, and low-gradient freestone streams. Fishing a blue-winged olive hatch can be a fairly easy proposition as these are the first sizeable mayflies to hatch in the spring and their sometimes long, drawn-out emergence can keep trout plucking bugs off the surface for a long, long time.
Best Baetis Emerger
Tied by Dave Klausmeyer
HOOK: Dry fly, sizes 16 through 20.
THREAD: Olive Ultra Thread 70 denier.
TAIL: Brown Z-Lon.
BODY: Olive peacock quill.
THORAX: Olive Superfine Dubbing.
WING: Snowshoe rabbit.
On cold days,an olive hatch will likely be brief because the water will only be warm enough to encourage the bugs to emerge during a short window of the day. Make the most of your time and work the riffles and runs with blue-winged olive nymph imitations before the bulk of the insects emerge. During high water events a fly with a flashback is also a good choice. Anything that can help attract the trout to your nymph when there are thousands of other flies in the drift puts the odds in your favor.
If the weather is warm enough, you’ll likely see a short, intense hatch of adults in the early afternoon. This is when some of the most productive dry-fly fishing occurs. When Baetis hatch, the nymphs slowly make their way to the surface. Once there, they shed their shuck and hatch into an adult. It’s a long, drawn-out process, and even when free, it takes a few moments before the bug’s wings are dry enough for it to fly away, making it an easy meal for trout.
There are times when trout rise freely to duns floating helplessly along the surface of the stream, though the intensity and duration depends on weather conditions. The worse the weather, whether it’s snow, rain or cold air temperatures, the longer the emerging nymphs or duns will be on the water.
However, don’t neglect spinner patterns. Anglers often attribute surface activity with adult patterns when in reality, the bugs are in their mating and egg-laying phase and a spinner imitation is a better choice. After adult Baetis have been hatching for a few hours and I sense the fish are becoming selective, I’ll switch to a spinner imitation and it fools even the pickiest fish.

(photo by Ted Fauceglia)
Hendricksons
The hendrickson (Serratella) mayfly is a favorite “super hatch” on waters in the eastern U.S. In fact, the bug’s name pays tribute to Albert Hendrickson, an angler from Scarsdale, New York, who also has an entire pool on the state’s Beaverkill River named in his honor.
Biot Hendrickson Spinner
Tied by Dave Klausmeyer
HOOK: Dry fly, sizes 10 through 14.
THREAD: Dark brown Ultra Thread 70 denier.
TAILS: Split microfibbets.
BODY: Light brown goose biot.
WING: Grizzly hackle trimmed flat.
While not as important in the Rockies, this hatch occurs from Maine to Georgia and as far west as Michigan. Like Baetis, the best time to encounter this hatch is when water temperatures rise, so while nymphing works through mid morning, the bulk of activity likely won’t occur until just after lunchtime. On warmer days the hatch can take place earlier and on cloudy, cool days, emergence generally occurs later in the day.
When hendricksons hatch, they are often so abundant it’s hard to tell whether the trout are feeding on the emergers, duns, spinners or nymphs, especially because all the stages can occur at the same time. Pay attention to how the fish are rising during and after the hatch. If a fish is gently sipping on the surface, it’s likely eating emergers. If the fish is swiping or splashing on the surface, it’s likely eating adults trying to take flight.
That said, don’t neglect nymph imitations. Trout often gorge themselves on hendrickson nymphs and appear infrequently afterwards. In fact, anglers typically blame high, off-color water for any lack of rising trout, though the real reason is the fish have so much of a good thing under the surface, there’s no reason to go topside. It is only when hatching activity ceases that you’ll find some heads poking up through the surface of the water, likely trout feeding on spinners.
The spinner fall generally occurs on warm evenings when the ambient temperatures are above 60 degrees, though even a light wind can dampen the event. Don’t be surprised to catch some of your largest trout of the season during this hatch as fish that would generally feed on larger food items will line up in slow tailouts and gorge on what seems like every hendrickson spinner falling into the water.
Click here to learn how to tie biot bodies.

(photo by Brian O’Keefe)
Skwalas
While this hatch is a spring highlight all over the West, it’s also important in the East, though the adults are a little smaller and lighter-colored than their Western cousins. The bugs prefer streams with fast, oxygen rich water that have a lot of clean rocks and boulders and a high gradient.
Skwala Stonefly Nymph
Tied by Dave Klausmeyer
HOOK: 3XL long nymph hook, sizes 10 through 14.
THREAD: Olive Ultra Thread 70 denier.
BEAD: Black brass or tungsten bead to match hook size.
TAIL: Olive goose biots.
ANTENNAE: Olive goose biots.
RIB: Copper or black UTC Ultra Wire, small.
BODY: Olive Mercer’s Buggy Nymph Dubbing.
WINGCASE: Olive/black Thin Skin Fly Specks.
THORAX: Olive Mercer’s Buggy Nymph Dubbing.
LEGS: Olive speckled rubber legs, medium.
Skwala stoneflies hatch from February through April, just before streams swell with runoff, depending where you’re fishing. Though generally, Southwestern and Western streams at lower altitudes see hatches sooner than areas in the Northwest or areas with higher altitudes or snow and ice.
Nymph the pocket water in the early morning because fish will hold in swift currents, feeding on naturals dislodged from the rocks. But as the day progresses, focus along the riverbanks. Skwalas typically migrate to shore, hatch in the dawn hours and fly into the trees, similar to most other stoneflies. Because the nymphs are awkward swimmers, trout will hold on the extreme edge of a stream, eating those making a break.
As the day progresses, blind-cast dry flies. Skwalas are prone to falling into the water, especially if the wind is blowing. Adults will return to the water during the late afternoon and evening to deposit eggs. Being on the water while these big bugs flutter and die can be one of the first great dry-fly fishing experiences of the season. If a dead-drift presentation isn’t working, add a slight twitch or skate your pattern.