On the connection of swifts with weather

For years I have been watching the movements of the "Spine-tailed Swift" (Chaetura Caudacuta), that species which comes down to us from China and Japan, and, after spending a few summer months here, departs again to those more northern climes.
I have noticed that the male and female ants of various species attain the winged state, and "swarm," or issue, in vast numbers from the nest, generally during the moist, muggy weather which precedes an atmospheric disturbance; the termites, or so-called "White ants," will often swarm during a light, warm rain.
It has, therefore, occurred to me that the frequent appearance of the Spine-tail Swift either during, or shortly before or after, disturbed atmospheric conditions, may be due to its winged food occurring more plentifully at these times.