River Intelligence / Observe Activity

Upper Au Sable development preview

Observe Activity

Turn visible clues into a starting water-column decision.

Watch before guessing

Visible behavior points to one box section.

Begin with the simplest useful clue. You do not need to identify the insect before choosing where to start.

What you noticeBegin inNext physical action
Repeated rises or insects taken on topSurfaceOpen the Surface decision card.
Bulges, backs, fins, or movement just below the surfaceFilmOpen the Film decision card.
Flashes below the surface or no clear surface activitySubsurfaceOpen the Subsurface decision card. Nymph, wet-fly, and streamer choices remain inside this section.

Learn more when useful

Extra observation can refine the fly after you have a starting section.

Optional ways to look more closely
  • Compare the size and general shape of insects on the surface.
  • Watch where and how often the same rise repeats.
  • Look at streamside vegetation and spider webs for recent adults.
  • Inspect a submerged rock only where doing so is safe, legal, and does not damage habitat.

Use these clues to refine size, then shape, then color. They are not required before you can begin.

Observation discipline

Write the clue before writing the conclusion.

Clue

“Three rises in the same smooth edge lane.”

Specific, repeatable, and useful.

Premature conclusion

“They are eating mayflies.”

Possible, but not yet proven. Begin with the visible water-column behavior.

Help refine this page

Did this make the next river decision clearer?

Tell us what helped, what remained confusing, and what a beginner would still need before using this guidance in the field.

Give Feedback
Give Feedback