I had some birds (presumably ospreys) catching fish when the feeder was going off. Ultimately, I changed the time the feeder went off to a different time frame and that seemed to make a difference.
I had a GBH that used to show up at my dock just before the feeder went off. It would flop down in the water when the feeder went off getting a fish right off. Then an extremely clumsy water take off with fish in tow. I had never seen a GBH take a fish in deep water before but this one got the technique down. Changed feeder times and didn't notice it on the dock any more.
