Hey kathyp, I'm trying to think of a solution to your swallow problem. It is my understanding that Gopher snakes will climb into trees to go after birds, maybe a few fake snakes that is brown and speckled like a gopher snake scattered around will help. Swallows are so darn fast and manuverable I am not even sure they fear owls, but maybe a fake owl. I have seen just recently, fake Peregrine Falcons like the fake owls. Considering that Peregrines are the fighter jets of the bird world, maybe that would spook off those swallows.