Swallows usually fly high overhead here. Only time they come down to the garden is some time in August when there is a some kind of hatching event -- it might be winged ants flying off at once. I can actually see them rising from the ground in swarms all over the yard. Then the swallows come down to skim across the garden..
It's a sight because the bigger dragon flies are making aerial sweeps too, and they somehow do not hit each other.