Swarming is the primary method of colony expansion for all termites. It’s the first sign people see, that lets them know when they have an infestation. Swarmers are usually present in mature colonies that are 3-5 years old, and the number of swarmers varies by species, and is uaually 1%-40% of the colony.
To prepare for the summer flight, the worker termites create an opening in the colony, which may be a break in the mud tube or a kick out hole, in the case of drywood termites. After the flight, the hole will be sealed. After the swarm starts, the termites usually are attracted too the light or a light source, thats why many people find termites on their window sills.
Swarmers are not good flyers, often depending on wind currents to disperse them. Some will lose one or more wings during flight, which you most likely will find on the floor. Most will not survive. It is estimated that 99% of a swarm is killed by predators, such as, other insects or birds.
The time of year swarmers occur, is based on environmental factors, such as temperature and humidity levels. Subterranean termites usually swarm in the spring and drywoods swarm in the fall, sometimes brought on by santa ana conditions in California. Termites have been swarming for millions of years and will continue to do so.