Go for the licsense, then find their roost, they roost in trees, in numbers, then shoot them if possible. Or, theres a river near me, that puts out straw-stuffed orange boiler suits with hi-viz waistcoats on, sorta techno scarecrows. They are definately getting braver though, you now get them diving thru your swim, 15 feet away, where as before, they would normally take flight when you dropped in a swim. I heard your now getting big inland colonies as well as the coastal colonies. Some sort of action needs to be taken.