Blue-winged Teal

On the morning walk I stopped at the top of the Gorge.  The water near the dam was clear but about half way down the gorge it changed color to a light green shade.  Looked like scum growing  over half of the water.   In all of the years I've walked past the Gorge I'd never seen scum.  While the Gorge is stagnant water - no ingress or egress - it is spring fed.  Plus it's been pretty cold every night and that scum would have to have grown since I came past here yesterday afternoon.  I couldn't figure it out.  My neighbor, Mr. Dearhamer, called in the afternoon and I mentioned it.  "Are you sure it's not pollen?"  he asked.  So for the afternoon walk I carefully made my way down the steep slope of the gorge to the water's edge.  The 'scum' was now all at that end (opposite the dam where it would have been easy to get at.)  Couldn't tell what it was so I dipped my walking stick in the water.  The stick came back clean.  I dropped a rock in the water and it made a dark hole in the green stuff which slowly filled in w/ tiny spots of material.  Not scum - probably pollen.   There are white birch trees growing down to the edge of the water and I'd noticed yesterday how covered w/ catkins they were.  That's a lot of pollen!  So glad I don't have hay fever or allergies!