The swarming flight of the newly emerged males and females is a common sight on a hot sunny afternoon in July or August.
This flight is their mating flight and males and females mate whilst in the air. After a few days the males die off. The females bite off their wings and either return to the original colony or find a suitable location to over winter. Normally by digging a tunnel under a stone, here she will remain until the following spring before she commences to lay eggs.
These eggs will start the new nest, they hatch in about 28 days, during this time the new young queen rests. When the larvae hatch she feeds them. This stage lasts about 23 days until new workers hatch, these new workers then start to nurse the new larvae, search for food and tend to the queen.
The workers lay scent trails as they move to guide other workers to food, this is why you often see them "marching" in such an organized way, this process carries on until the next mating flight and everything starts again.