Flying ant day: when it happens and why ants fly

What flying ants are

Flying ants are not a separate kind of ant. They are the winged males and young queens of an ordinary colony, raised over the summer to leave the nest, mate and start new colonies. In the survey, close to 90% of the flying ants reported were black garden ants, the small dark ant that nests under lawns, paths and patios.

The flight is a mating flight. The males die soon after mating. A mated queen comes down, sheds her wings and looks for a crack or patch of soil to start a nest of her own.

What the survey found

From 2012 the Royal Society of Biology and Professor Adam Hart of the University of Gloucestershire ran a Flying Ant Survey for three summers, using sightings sent in by the public. The results were published in the journal Ecography.

• Flying ants were seen on as many as 96% of days between the start of June and the start of September.
• Ants flew only when it was warmer than 13°C and the wind was below 6.3 metres per second.
• Every summer day with an average temperature above 25°C had ants flying somewhere in the UK.

So the idea of one national flying ant day is a myth. Each colony waits for the right weather where it is.

Why it feels like one day where you live

Nests in the same street share the same weather. After a cool spell, the first warm, still afternoon can send many of them up within a few hours, and the pavements, walls and windows fill with ants. A town a few miles away may have had its swarm a week earlier.

The swarm also draws a crowd. The Royal Society of Biology notes that flying ants are an easy meal for birds such as gulls, which is why you may see gulls circling and swooping over rooftops on a warm summer evening.

Are flying ants a problem?

Usually not. Black garden ants are a nuisance, not a danger, and the flight is over within hours. Spraying the swarm kills harmless insects, does nothing to the nest underground and leaves insecticide where children and pets walk. Brush or vacuum up the ones that get indoors and close the windows until it passes.

A crowd of insects coming and going from one hole in a wall or the ground for days on end is something else. That pattern points to a wasp nest or a bee colony, not ants. Our wasp, bee or hornet guide explains how to tell.

Keeping them out on a flying day

On a warm, still afternoon in summer, shut the windows on the side of the house nearest the lawn or patio until the evening. Check the gaps around door frames and along the bottom of patio doors, because the same gaps let ant workers in for the rest of the year.

The workers are what cause trails in the kitchen later in the summer, not the flying ants. Keep sweet food sealed and wipe up spills, and a trail is less likely to start.

Flying ants coming from inside the house

If the ants come out of a gap in a floor, skirting board or wall inside, the nest is under or in the building. Note the spot. Once the flight has finished, seal the gap and use ant bait for the workers in the following weeks, as our DIY ant guide explains. Ant bait works because workers carry it back to the nest.

Call a professional if ants keep appearing indoors after the flight, or come from more than one place. See ant control for what a visit involves and the cost. Some councils treat ants but not flying ants, so check what your council covers before you book.