Don't worry - they won't be about for long. The swarms consist of Queens and males setting off from the nest in search of pastures new. During their flight the Queens' only interest is to mate with the males. Once they've had their quickies, they find a new place to build a nest, chew off their own, now redundant wings and lay their first eggs. They do little more until they hatch. The males only live for a few days longer and will not take to the air again.