Information and answers to frequently asked questions about wasps

Do wasps swarm?

Wasps generally do not swarm in clusters the same way as honey bees do. The only time that they will appear to swarm is when the nest has been treated, or the entrance has been blocked, and the foraging wasps are trying to get back into the nest.
Wasp will swarm feed, but this is not the same as a honey bee swarm. Swarm feeding is where scout wasps find a food source, then go back to the nest and report their findings, recruit back up to try and dominate this new source of food and defend against wasps from other colonies.
If you find yourself with a cluster of what appear to be wasps, it is most probably honey bees. When honey bees swarm and relocate, they usually choose a tree branch or other object to land on, the entire swarm will cluster together around the queen.
You can view images of honey bee swarms here to compare.

Why do I have a wasp nest every year?

If you end up getting a wasp nest every year, there is no particular reason for this apart from the location is a good one for them to build their nest. If you live in a house with an old roof, there will be many entrances for the wasps to use, and the tiles will be old with gaps between them. New homes are not impervious to wasps, but the lack of available entrance points reduces the chances of having a nest.

What time of year do wasps build nests?

Despite common beliefs, wasps and hornets NEVER reuse an old nest from a previous year. They always build a new one. Occasionally they will build onto the side of an old nest, but they will not use the old one.
Wasps start building a brand new nest in the spring. This happens when the overwintered queens emerge from hibernation. Once these new queens emerge from hibernation, they find a suitable place to build a new nest. This activity starts as soon the weather is warm enough, and the frosts have all but finished. The nest starts off small, and there is only the queen, but as soon as she has laid eggs and these have hatched and gone through the development stage and emerged as adult wasps, then these workers take over the nest building process.

More info on the life-cycle of the wasp

Are wasp and hornet nests dangerous?

A wasp nest itself is not dangerous, but the individual wasps when working as a unit can be formidable. Wasp venom can be life-threatening to certain susceptible individuals who are allergic. But if stung enough times, even people who are not allergic can be overwhelmed by wasp venom. 30 stings or more can be deadly, and the effect of wasp stings is accumulative, i.e. the more stings you receive, the worse your reaction will be. There are usually a few deaths each year from wasp attacks, which sounds horrific, but when compared to the number of wasp nests each year and the number of people living in the UK, it is not as bad as it sounds. The temper of the nest or mood is determined by the queen. If she is a particularly nasty individual, this behaviour will be passed on to her offspring, and the entire nest will be aggressive.

Do the local council treat wasp nests?

Depending on where you live, most council’s do provide treatments for wasp nests, however, it should be noted that usually, councils do not prioritise wasp nests and the waiting list can be up to 4 weeks long. Independent pest controllers usually treat wasp nests on the same day as they are called.

Should I block the entrance to a wasp nest?

If there is one piece of advice that you should heed it is this: DO NOT BLOCK THE ENTRANCE TO A WASP NEST! Blocking up the entrance is the worst thing you can do, the wasps will instantly become agitated and try to find another way in and OUT! Nests on houses that have had the entrances blocked usually chew their way out to the inside of the house. This makes matters far more complicated and what should have been a straight forward process now becomes difficult to treat. Wasp can and will chew through plasterboard, wood, insulation, polystyrene and other various materials to achieve their goals. Please refrain from using expanding foam, putty, silicone sealant or any other builders materials to treat a wasp nest. Please do not set fire to a nest or nest entrance.

Identifying wasp nests

If you suspect that you have a wasp nest but are not sure where it is, the first place to look is outside, wasps predate on smaller insects which live outdoors. If the nest is on your property or building, the wasps will be arriving and leaving via an entrance-exit point.
Usually, they build their nests in the attic space or behind fascias. So start off by looking at the roof. Pay attention around the gutter areas as this is usually a good point for them to gain entry, under the tiles. As the year progresses, the nests get larger and contain more wasps, so the entrances become more easily identifiable. You will see wasps arriving and leaving from a specific location every few seconds. If you cannot see any sign on the roof, check air bricks, another favourite place for them to get into.
Take a look at our information page on how to find wasp nests

If there are no signs on the building, the next obvious place would be garages, garden sheds, outbuildings etc. Keep in mind that common wasps will nest in the ground. European wasps only nest in bushes. A European wasp nest will be visible and resembles a large grey ball.

Hornet nests

Hornet nests are similar to wasp nests and are made in the same way from chewed wood, the actual nest is slightly larger than a wasp nest, but will not contain as many individuals. Hornets prefer to nest under cover, but they will build their nests in old tree stumps, thatch and also in underground cavities (but this is rare). Naturally, people are wary of hornets because of their size. Their sting is powerful, but they are generally not as aggressive as regular wasps.
Read more info on Hornets

Can wasps build a nest in a hole in the brickwork of house?

Wasps frequently use holes in brickwork to gain entry into the cavity of a wall. Wasps can build their nests in any shape that they require to fill the available space. Most people think of wasp nests as being a round ball, but this is not always the case, they can make their nests long and flat.

Should I burn wasp nest?

Setting fire to a wasp nest is the last thing you should do. You may kill a few, but are more likely to agitate the nest and set off their defensive mechanism. People are likely to get stung. During the day, a large proportion of the wasps are out foraging and setting fire to the nest will not kill these individuals. Upon their return, they will become confused as to where their home is. As more of them arrive home, their numbers will build up and they will become a worse problem than before.