Hendrickson
Also called Ephemerella subvaria, Red Quill, Hendrickson hatch
A Hendrickson is a spring mayfly hatch best known on Eastern trout rivers. Anglers use the name for the insects and for fly patterns that match their duns and spinners.
- Group
- Mayfly hatches
- Category
- Entomology & forage
- Level
- Intermediate
- Water
- Freshwater
Last updated
What Hendrickson means
In most trout talk, “Hendrickson” means the mayfly species Ephemerella subvaria and its hatch. It’s a classic early-season event on many freestone rivers in the Northeast and Appalachians, and it can overlap with other spring mayflies depending on weather and elevation.
Anglers usually break it into stages: nymphs before the hatch, duns during emergence, and spinners later when adults return to lay eggs. Fly shops and hatch charts may list “Hendrickson” and “Red Quill” separately; in many places those names get used for closely related mayflies and for different color forms, so it pays to match what’s actually in the air and on the surface rather than the label.
Why it matters on the water
Knowing what people mean by “Hendrickson” narrows the playbook to spring mayfly tactics: nymphs ahead of the hatch, then a dun or emerger, then a spinner toward the end of the day. That keeps fly changes deliberate instead of random.
It’s one of those hatches where timing matters as much as pattern. If duns are coming off but trout keep showing noses and not eating a standard dry, switching to an emerger or cripple profile often lines up better with what they’re taking. If the riseforms turn subtle and sippy later, thinking “spinner fall” keeps you from staying stuck on a dun imitation.
Read next
- Blue-winged olive“Blue-winged olive” (BWO) is the common fly-fishing name for several small mayflies in the Baetis group. Anglers use it to describe the hatch and the flies used to match it.
- March brown“March brown” is a common name for several medium-to-large spring mayflies and the hatch events tied to them. The name can mean different species depending on region.
- SpinnerA spinner is a dry fly that imitates an adult mayfly after it has mated and fallen spent on the water, usually with wings laid flat to the sides.
- Sulphur“Sulphur” is a common hatch label for small yellow mayflies, most often in the genus Ephemerella. Anglers use it to match pale yellow duns and their evening spinner falls on many trout rivers.