My wife and I were waiting for the light to turn green at an intersection. We noticed what looked to be 15 or so swallows flying through, around, landing and taking off again, right at the intersection. We started paying attention and this seemed to be common. The question is: What would be causing the birds to gather at intersections? Does anyone know the Straight Dope?
IIRC, swallows are bug-eaters. If this happened at night, they may have been working the cloud of bugs gathered around the lighted intersection. If it was daytime, I dunno.
–Nott
Swallows are diurnal, so lights are unlikely to be the explanation.
Swallows feed on small flying insects. The only thing I can think of is that if the streets were lined with tall enough buildings, air eddies at intersections could cause local concentrations of insects. But that’s pure speculation.