[Persquen]

I have recently noticed many wasps (not a swarm) flying around just above ground level and confined to an area of around 3 sq m. They arrive when the sun comes out in the morning and are gone when it gets cooler. There are no obvious signs of a major nest but do notice little mounds of earth (miniature molehills) with the occasional wasp emerging from small hole. There is no consistent entering of any main hole to indicate a nest and no signs of wanting to attack when area approached. I didn't think at this time of year wasp would be forming a new nest in the ground. Any body any ideas as to what is going on.
Thankyou
Persquen