I had the same problem the last 2 winters. Tried a powerful handheld green laser and it had zero effect, worked to scare geese, ducks and egrets but no effect on the cormorants. I found over a dozen dead and dying BG after a cormorant feeding frenzy, too big to swallow or just so much food they didn’t eat every fish they grabbed. The good news is the following days I didn’t see the normal Bg feeding at feeders and thought they were dead but in fact they just quit feeding and hid in structure. Once the cormorants disappeared the BG came back and fed well with no noticeable decrease in numbers.
