What is Flying Ant Day?

Flying ants often seem to appear on the same day in different locations in the UK – flying ant day. Most ant colonies start with a flying ant - when young queens leave the nest to found their own colony.

However, our citizen science project, the Flying Ant Survey, has found that there is not actually one day where these ants all appear all at once, but that, depending on weather conditions, the ants can start emerging and flying at almost any point during the summer months, and won't all necessarily appear only on one day either.

The Royal Society of Biology Flying Ant Survey

Starting in 2012 and continuing for three years, Professor Adam Hart from The University of Gloucestershire and the Royal Society of Biology ran an annual online Flying Ant Survey to find out where and when people were seeing flying ants.

One of the primary findings from the survey  was that there is certainly not only one flying ant day; the frequency in which the flying ants appear changes each year and is dependent on the weather.

Colonies also don't exhibit any significant geographical co-ordination when it comes to taking to the skies; one garden may see flying ants on one day, with neighbours seeing them weeks or even months later.

Weather was confirmed to be absolutely critical when it came to flying ants emerging however, only emerging if it is warmer than 13C and when wind speeds are less than 6.3 metres per second. During the course of the study, every day in the UK summer that had a mean temperature above 25C had ants flying somewhere.

The findings have since been published in the journal Ecography, and a summary of our findings can be read on the BBC.

Flying Ant Day FAQs

Why does flying ant day occur?

This is a day when males and new queens leave the nest to mate, with many ant colonies doing so on the same day when the conditions are just right. It is the way that many ant species, including the black garden ant Lasius niger,leave their previous nest to begin new colonies.

Our survey found that there is often not just one flying ant day but on as many as 96% of days between the start of June and the start of September flying ants are spotted.

The pattern of flying ants differed massively between years. For example, in 2012 there were just a few days in late July and a few more in mid-August where around 80% of the flying activity was focused.

Sometimes the same ant colony may produce flying ants more than once over the course of the season.

Are flying ants all of the same species?

After the first year running our survey, we asked some people, "super-engagers" who were keen on doing more, to send us samples of the flying ants from their sightings.

Using the thousands of ants returned to us we were able to determine that close to 90% of flying ants were from just one species - the black pavement ant Lasius niger.

What are the conditions needed to encourage flying ants to appear?

Weather turns out to be an absolutely critical factor in triggering ants to fly. By comparing records of flying ants with the nearest weather station data, we were able to untangle some of the factors that trigger ants to take to the sky.

Ants only flew when the temperature was above 13C and when the wind speed was less than 6.3 metres per second but overall ants like it calm and warm. During the course of the study, every day in the UK summer that had a mean temperature above 25C had ants flying somewhere.

The records sent in by the public also showed that ants are excellent at short-term weather forecasting. By examining the changes in weather in the days before and after each flying ant event, we discovered that ants were more likely to fly on days that were warmer and had lower wind speeds than the day before.

How do ants mate during this period of the year?

Ant colonies start with a female flying ant that will have left their previous colony to begin a new one. Unlike the female worker ants we see throughout the year, the queen starts her adult life with wings, and is noticeably larger.

Both males and females take to the skies, travelling away from their nest in a bid to find mates from other colonies and settle down in suitable conditions to begin their own colony.

When far enough away, the females and males commence breeding, with mating taking place during flight and the male dying shortly after. The fertilised female then lands, chews off her wings, then goes about creating a new colony or finding an existing one and starts to produce offspring.

What do flying ants contribute to the environment?

Ants contribute a lot throughout their lifespan, including aerating the soil they burrow into and recycling nutrients and returning detritus back into the earth. Their activity allows for more oxygen and water to reach the roots of plants and they can even improve soil fertility and help control pests.

When in flight, they can be a target for larger predators; emerging in large numbers increases the likelihood of at least some ants surviving predation and being able to mate but does mean they can be a quick and easy source of food for birds like gulls too.

Are they harmful and should I try and get rid of them?

Flying ants are not harmful, so if some emerge in your garden or elsewhere it’s best to leave them alone as they’ll disappear once they fly off within a few hours.