ok, so i've been getting this weird grey/white film on the water surface for a couple weeks, wasn't sure what it was. figured it out today. the pigeons nesting ont he balcony above have been using my wine barrel sized pond as their own little day spa. look how comfy they are, i;m only 3 feet away, pointing a digital camera at them. i was close enough to get splashed. they each jumped in 4 or five times splashed around, really dunking themselves and then climbing out. they preened their feathers for a while, and then sat in the sun to dry out.
at least it's not some weird mold or something.