Is this wire something you already have on hand? If so I say give it a try but I personally think 18 is too light. I would use at least 14 for wind and birds. I only use 12 AWG solid naked copper myself for a wire antenna. It is very strong against heavy winds, is somewhat flexible, and very workable with deployment. Very tough stuff, it develops a patina coat from the salty, moist air here, but underneath that coat remains the full strength and signal surface of that heavier gauge.