Codorus Creek fly

[laszlo]

I fished Codorus Creek yesterday afternoon. Thought I'd get out before the big storm hits tomorrow and stirs things up.
I noticed the last few times I've been on the stream I see alot of trout rising to something invisible. There are no hatches, and the fish seem to be sipping something very small. I've caught a few using a small caddis but this fly is much smaller. Anyone seeing this on other streams? Any thoughts as to what they are feeding on?

 

[Fishidiot]

My guess would be midges - probably too late for tricos. There could also be a whole bunch of nymphs that may be active just under the surface.
Finally, don't rule out terrestrials. With the warm weather and breezy conditions we've had lately it could be flying ants or some other small bugs.

 

[laszlo]

I think you're right about midges, the rises are no more than dimples. They wouldn't take an ant. I did inspect the trees at the parking area at Brown Rd and found a number of red beetles on the trunk. This was done while waiting for my wife to arrive with jumper cables because my car had died.