A random and dense latticework of mono-filament line, 25 to 30 pound test, is well documented throughout Florida for keeping shore birds off of, out of, and away from pool decks and patios of beachside hotels and motels, restaurants, and bar and grills. If you have exposed wood framing, it should not be difficult to discourage these birds with mono-filament line.
Glad to talk propane cannons and wildlife discouragement together on this Board.