4 min read · Updated 2026-03-10
Eastern subterranean termites — the species of concern in New York — produce winged reproductives called swarmers. A swarm is the colony's way of starting new colonies, and it is often the only time termites become plainly visible to a homeowner.
When swarms happen here
In the Hudson Valley, swarms generally occur on warm, calm days in spring, most often from roughly April into June, and frequently in the day or two following rain. Warmth and moisture trigger the event, so an early warm spell can move it up and a cold, wet spring can push it later.
Swarmers are weak fliers and are drawn to light, so they typically show up at windows, sliding doors and basement light wells.
Termite swarmer or flying ant?
- Termite swarmers have a straight, thick waist; flying ants have a pinched waist.
- Termite wings are all roughly the same length and shed easily; ant wings are unequal, with longer front wings.
- Termite antennae are straight and beaded; ant antennae are elbowed.
What to do if you see a swarm
Collect a few specimens or discarded wings in a container or take a clear photo — identification is much easier with a good image. Note exactly where they appeared, since indoor swarms point to activity in or under the structure.
A swarm does not mean the house is destroyed, but it does mean a colony is nearby and the property should be evaluated.