actually my fishing line works great. I watch the hawks try to find an openening but they cant seem to be able to. Just make sure the lines are no farther than 5 feet apart 4 feet is even better. You can also use that thin rope they use when marking lines for masonry work if you dont mind the string being seen. If you are going for unnoticable except by the hawks then use the fishing line, jus make sure it is higher than the tallest person who may walk out there. I make the mistake of only having mine 6 feet high and nearly too the head off my friend the other day.
