Flipping Rocks and The Drift Part 1

 Many years ago, I started to pay more attention to what was actually in the water, than what I thought was in the water.   My home waters of The Croton Watershed in Southeastern NY, and even The Housatonic and Farmington Rivers in CT, are all highly pressured rivers.   I was buying and tying standard flies.  I was using the exact materials that recipes called for. Also, I was fishing these flies "when the time was right".  I would fish Hendrickson nymphs during the Hendrickson hatch.  I would use Caddis nymphs and pupae when I knew the Caddis were getting ready to emerge.  I was fishing by the book you could say.

     I was having good success until a humbling day on one of the rivers.  I struggled and didn't catch a single fish.  There were fish sporadically rising, and fish were feeding, but I couldn't get anything going that day.  The whole way home I thought, was it my drift, maybe my tippet was too heavy, maybe they could see me, or did I use every fly I could?  The answer to the last question was the one that got me thinking.  So the next time out, I flipped some rocks and matched what I saw on the rock, and what I had caught in the net.  Well I got the same result as I did the previous outing.  Now I was very agitated at this point.  I mean I had matched what was under the rocks, that's what they were eating wasn't it? 

     I did some research on the subjects and I found some interesting things about flipping rocks and the drift.   Yes you can flip rocks and catch the bugs that are underneath them.  Taking a good close look at these insects will help you modify your flies and maybe change the materials that you use when tying.  For example, I blended my own dubbing to match the exact shades of the various Caddis fly larve in one of my home rivers.  I even modified my own WD-40, to match the tiny mayflies in the summer.  Making slight modification in your patterns, can turn on a highly pressured trout.

     To get a good idea of what's actually in the water you have to understand the drift.  The drift is the movement of aquatic insects from one place to another using the current.  To really become an accomplished angler, you must understand the types, and how to use those types to your advantage. 

Behavioral drift is the most important type of drift for you to understand.  Its is when nymphs and pupae use the current to move from one place to another to find food, new shelter, or less crowded conditions.  There are 3 peak times, an hour before and after first light, and hour before dark, and from midnight to about 2 am.  During these movement times, the food available to the trout is increased which sparks feeding activity.  Clouds can increase the time on how long the Behavioral Drift lasts, and sun can have the opposite effect.  To find out what types of insects are in the drift, sample the water by setting up a screen to capture what's in the drift.  The screen should be left for a prolonged period of time during one of the peak times. 

     Some species such as Olives and Midges can be in the drift almost all the time.  This is called Constant Drift.  You can measure the Constant Drift at any time during the day, but you should sample at different times of the day. 

     Another type is call Catastrophic Drift.  This occurs when high water pushes entire populations of underwater insects into the drift.  The high water can be caused by run off, rain, or even releases of water. 

     Knowing what's under those rocks can help you choose what to use during these types of drift.  Remember the types of insects, their sizes, and numbers will vary from season to season.  Using a nymph from a hatch ahead will also increase your catch rate because that is what the fish are seeing during the insects movement.   Fishing a Hendrickson nymph during the actual hatch  might not be as successful as before the actual hatch because the fish will be keyed in on the emeregers and duns, and possibly the next hatch's nymph. 

     In one of my home rivers, the winter fishing has been very slow compared to the past few years.  We have had a very cold winter here in the Northeast, but right now there is nothing in the drift.  I cant wait for that first catastrophic drift to occur to get some food moving in the water and get the trout feeding again!


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  1. Excellent post, Frank. You've got some real gems of knowledge in this post and I appreciate it!

  2. Wow, this is one if the most interesting posts I've seen anywhere.... Lots to think about-thanks for sharing this info

    1. Thanks Chris! I have done some HW on the subject, lots of good info out there on it, I have just tried to give you a little that will hopefully help you get some more fishi to the net! Im going to do a couple of more parts ans the seasons and water change!