I don't have a remedy but have to admit they are a pest.
You can chase a whole lot off the bow and by the time you are back in the cockpit they are all up at the stern having a nicle little chatter among themselves as though nothing had happened. Now, if I had an air-rifle,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,