Every monsoon season here, "spectacular swarms of flying ants are a common phenomenon.
Usually following 3-5 days of heavy rain, the winged reproductive forms emerge from the
colony in large swarms. Such swarming behavior is usually synchronized by other nearby
colonies so large numbers of winged ants suddenly appear. All mating for the species
takes place, often over the course of a single day. The males die and the mated females
disperse to attempt establishing a new colony.
One behavior associated with some ants during mating swarms is "hilltopping". This refers
to their aggregation around prominent points of a landscape where they search for mates.
A large tree, the chimney of a roof or even a tractor moving across the plains might serve
as such an "action site" for swarming winged ants". Unfortunely for me, right smack in front
of our doors to the outside seem to be a favorite point!