Quick answer: Termite swarmers in fall are winged reproductives leaving an established colony to start new ones. In the Willamette Valley, small dark swarmers on a warm afternoon after the first soaking rains are usually western subterranean termites; big swarmers at the porch light on a mild evening are Pacific dampwood termites. Swarmers emerging inside the house point to a colony in or under the structure. Get it inspected.
Key takeaways
- Western subterranean termites swarm on clear afternoons after a soaking rain, and Washington State University reports that on the west side of the Cascades it happens mostly in fall.
- Pacific dampwood termites, the termite we find most often under valley homes, fly on warm evenings in late summer and fall and head for lights.
- Straight antennae, a thick waist and four equal wings mean termite; elbowed antennae, a pinched waist and larger front wings mean ant.
- Do not spray a swarm. Collect a few insects, note where they came out, and book an inspection.
Why do you see termite swarmers in fall in Oregon?
Because fall weather is the trigger. A mature colony raises winged reproductives and releases them when conditions are right, and for both of Oregon’s structure-infesting termites, those conditions arrive with the first rains.
The western subterranean termite (Reticulitermes hesperus) swarms in the afternoon on clear days after a soaking rain, in spring or fall, according to the University of California Statewide IPM Program. Washington State University Extension adds that in western Washington, swarming is predominantly a fall event, and the Willamette Valley shares that weather. Around Salem, that means the first bright, warm afternoon after an October storm.
The Pacific dampwood termite (Zootermopsis angusticollis) runs on a similar calendar. WSU notes that its flights usually happen on warm evenings in late summer or fall, especially after rains, and Oregon State University Extension adds that the swarmers are often attracted to lights. That is the big, clumsy insect bouncing off your porch light in September.
Once they land, swarmers drop their wings, pair up and look for a place to start a colony. Most fail. The ones that matter to you are the ones that came out of your walls.
Is it a termite swarmer or a flying ant?
Check three things: antennae, waist and wings. WSU’s test is the simplest we know. A termite has straight, beadlike antennae while an ant’s are elbowed, and a termite’s four wings are all the same size while an ant’s front wings are noticeably larger than the back pair.
The waist settles any doubt. Termites are thick through the middle, almost tube-shaped. Ants have a pinched waist you can see without a magnifier.
Winged ants fly in this region too, so do not assume. If you are unsure, put a few insects in a sealed bag or on a strip of clear tape and text us a photo. We would much rather identify an ant than miss a termite.
Subterranean or dampwood: which termite is swarming at your house?
Size and color tell you most of it. Subterranean swarmers are small and dark. Dampwood swarmers are big, up to an inch long or more including wings, and range from cream to dark brown, according to WSU.
| Feature | Western subterranean swarmer | Pacific dampwood swarmer | Flying ant |
|---|---|---|---|
| Size | About 3/8 inch including wings | Up to 1 inch or more including wings | Varies by species |
| Color | Dark brown to brownish black | Cream to dark brown | Black, red or brown |
| Antennae | Straight, beadlike | Straight, beadlike | Elbowed |
| Waist | Thick | Thick | Pinched |
| Wings | Four equal wings, longer than the body | Four equal wings, longer than the body | Front pair larger than the back pair |
| When they fly | Clear afternoons after soaking rain, fall or spring | Warm evenings in late summer and fall, often after rain, toward lights | Varies by species |
| Where the colony lives | In soil, reaching wood through mud tubes | Inside damp wood; no soil contact needed | Soil, wood or wall voids |
| A swarm indoors suggests | A colony under the structure with a route in | Wet, decaying wood in or on the structure | An ant nest in or near the house |
We find both in the valley, but dampwood evidence turns up far more often than subterranean in the crawl spaces we inspect around Salem, usually in a sill plate or pier that has been wet for years. Our post on damp wood termites covers their habits in more depth.
What does a termite swarm inside your house mean?
Almost always, an established colony in or under the structure. WSU calls termite swarms coming from the home probably the most obvious sign of an infestation. A swarm in the yard is different: UC IPM notes that swarming termites outdoors do not necessarily mean your house is infested, though it does mean a colony is close.
Indoor swarmers come out of baseboards, window frames, cracks in a slab, the crawl space hatch or a bathroom floor. They fly toward windows and light, so you usually find them, or just their shed wings, on sills and in spider webs.
- Do not spray. It kills a few swarmers and hides the evidence an inspector needs.
- Collect several in a sealed bag or on clear tape, wings included.
- Note the exact spot they emerged and take a photo before you clean up.
- Look for mud tubes on the foundation and crawl space piers, and for more wings on sills.
- Book an inspection and hold off on repairs until it is done.
If you found the swarm late and only have wings, that still counts. Our guide to early signs of termite damage shows what else to check while you wait.
Why moisture and wood-to-soil contact matter in the Willamette Valley
Because both of our termites need moisture, and our climate delivers it from October into May. UC IPM notes that subterranean termites require moist environments and nest in or near the soil. OSU Extension says dampwood termites usually gain a foothold where timbers touch the soil directly, but they also move in where wood stays wet from poor drainage or faulty plumbing.
Walk your foundation after the next rain and look for siding or trim touching soil or bark, deck posts and porch steps sitting on dirt, downspouts dumping at the foundation, firewood on the ground against the house, and a crawl space with standing water or no vapor barrier. UC IPM’s rule of thumb is a 12-inch barrier of concrete, coarse sand or similar material between the soil surface and structural wood.
Older homes in Dallas and Salem’s mid-century neighborhoods often have sill plates within inches of grade and crawl spaces that stay damp all winter. That combination is what produces termite swarmers in fall, and it feeds the fungi that soften wood ahead of them. Our guide to crawl space moisture, mold and wood-destroying pests walks through fixing it in the right order.
When to call a professional
Call as soon as you find swarmers or wings indoors, mud tubes on a foundation or pier, or wood that sounds hollow or crumbles under a screwdriver. UC IPM notes that an inspection by a licensed professional is required before any treatment, and that is how we work.
A termite inspection with AAA Pest covers the exterior foundation, the crawl space (piers, sills, joists and plumbing areas), the attic and the interior. We look for mud tubes, damaged wood, the small hexagonal fecal pellets dampwood termites leave behind, moisture readings and the conducive conditions above. Then comes the plan: for subterranean termites, a treatment aimed at the colony’s route between soil and wood; for dampwood termites, moisture correction and removal of infested wood, with treatment where it is warranted.
Our termite control service uses EPA-registered products applied according to the label, with family- and pet-considerate options, and we tell you exactly what to expect, including any re-entry times. If the inspection turns up beetle exit holes and powdery frass instead of termites, our wood beetle service takes it from there.
AAA Pest Exterminators has been family-owned and operated in Salem since 1997. There are no long-term contracts, and we explain what we found either way.
Frequently asked questions
Do termite swarmers in fall mean my house has termites?
If they came out inside the house, very likely yes. Washington State University Extension describes swarms coming from the home as the most obvious sign of an infestation. Swarmers outdoors, on a fence or in the lawn, mean a colony is nearby but not necessarily in your structure. Either way, an inspection settles it, and it is worth doing promptly.
How do I tell a termite swarmer from a flying ant?
Termites have straight, beadlike antennae, a thick waist and four wings of equal size. Ants have elbowed antennae, a pinched waist and front wings larger than the back pair. Hold one against a white piece of paper and the waist alone usually tells you. If you are still unsure, text us a close-up photo.
What should I do with the swarmers I find?
Do not spray them. Collect several in a sealed bag or on clear tape, including any loose wings, and note exactly where they came out. Photograph the spot before you vacuum. Then check the foundation and crawl space for mud tubes and call for an inspection. The insects and the location are the two things an inspector needs most.
Do dampwood termites damage houses?
They can, but only in wood that is already wet. A dampwood colony in a sill plate or deck post means that wood has a moisture problem, usually from soil contact, a leak or poor drainage. Fixing the moisture and removing the infested wood is the core of the solution. An inspection also checks whether decay fungi are involved.
When do termites swarm in Oregon?
Western subterranean termites swarm on clear afternoons after a soaking rain, mostly in fall west of the Cascades and sometimes in spring. Pacific dampwood termites fly on warm evenings in late summer and fall, often after rain, and come to lights. In the Salem area, September through November covers most of the activity people notice.
Pests in the nest? Don’t stress. Call the best.
Family-owned and operated in Salem since 1997. No long-term contracts. Serving Salem, Keizer, Albany, Dallas, Woodburn and McMinnville.
Not sure what you’re looking at? Text us a photo and we’ll help identify it.
