You walked outside, looked up at your fascia, and there they are: perfectly round holes drilled into the wood. Maybe just one, maybe a dozen lined up. You searched, and every result told you the same thing: carpenter bees.

Here’s the honest answer most pest control sites won’t lead with: in Minnesota, those holes are usually not carpenter bees. Large carpenter bees (Xylocopa virginica) — the species that drills the classic half-inch round holes in fascia, deck rails, and cedar siding — are at the extreme northern edge of their range in Minnesota. According to the University of Minnesota Bee Lab, only a handful of confirmed sightings have ever been recorded in the state. Two specimens were collected in 1969 and 2016. A single male was photographed in Ramsey County in 2025. That’s the cumulative documented record. In Wisconsin and Iowa they’re a real homeowner pest. In Minnesota they barely register.

So if you’re staring at round holes in wood around a Twin Cities home, the actual likely culprits, in order:

Woodpeckers — by far the most common cause of round holes in exterior wood in Minnesota
Old construction holes — nail holes, plumbing penetrations, wiring access points, sometimes painted over decades ago
Powderpost beetles — small pinholes (1/32 to 1/8 inch) in indoor hardwood
Actual carpenter bees — possible in southeast Minnesota and the immediate Twin Cities metro, but uncommon
Carpenter ants — irregular oval kick-out openings, not really “round” (see our sawdust articles)

This page walks you through how to tell which one you have. The answer changes what to do next, and in many cases the answer is “do nothing” — woodpecker damage and old construction holes don’t need a pest control company.

The 30-second answer

Look at the hole, where it is, and how many there are.

Half-inch round holes, smooth circular bore, in unpainted cedar fascia / deck / pine eaves, with yellow staining or sawdust below → possibly carpenter bees (rare in MN, but check)
Small pinholes, 1/32 to 1/8 inch, in indoor hardwood floors / beams / furniture, with fine powder below → powderpost beetles
Variable-size holes (often 1–3 inches wide), irregular, often clustered or in a vertical line, in cedar siding or trees → woodpeckers
One or two perfectly placed round holes near outlets, pipes, or trim, no recurring damage → old construction
Irregular oval slit-shaped openings, often with coarse sawdust below → carpenter ant kick-out hole, see our sawdust article

If a row jumped out, skip to that section. If you’re unsure, keep reading.

Candidate 1: Woodpeckers (the most likely answer in Minnesota)

Minnesota has at least seven species of woodpeckers, and the ones most likely to damage your house are downy woodpeckers, hairy woodpeckers, and pileated woodpeckers. They drill into exterior wood for three reasons: foraging for insects (especially carpenter ants and beetles inside the wood), excavating nest cavities, or drumming during breeding season to claim territory.

What woodpecker damage looks like

Variable size. Holes can range from a quarter-inch (downy woodpeckers tapping for insects) to several inches wide (pileated woodpeckers excavating for carpenter ants).
Often clustered. Woodpeckers tend to keep working an area once they find food. You’ll often see multiple holes in a vertical or horizontal line, or grouped damage on a single board.
Irregular edges. Unlike a carpenter bee’s clean half-inch bore, woodpecker holes have ragged edges where the bird’s beak chipped wood off rather than drilling smoothly.
No insect debris below. No sawdust pile, no powder, no yellow staining. The wood chips fall as the bird works and don’t accumulate.
In cedar siding, fascia, or trim — especially older, weathered, lightly painted wood. Pileated woodpeckers in the Twin Cities will also work on dead trees, telephone poles, and sometimes wood-shake roofs.

The carpenter-ant connection

Here’s the wrinkle that changes the diagnosis: woodpeckers in Minnesota frequently drill into homes specifically because the wood already has carpenter ants inside it. They can hear or sense the colony, and they’re after the protein. So if you have a woodpecker repeatedly working the same area of fascia or siding, the bird is the visible problem but the ant colony is often the underlying problem. Replacing the damaged wood without addressing the ants just gives the next generation of woodpeckers a fresh target.

This is probably you if…

The holes are in cedar siding, fascia, soffits, or trim — exterior wood you can see from outside
You’ve heard hammering, drumming, or tapping sounds, especially in early morning during spring (March–May)
The damage is irregular, not cleanly round
There’s no sawdust pile, no yellow staining, no powder below
The holes are clustered — multiple in a small area

What to do

If the holes are recent and the wood is repairable: Get a pest professional to check whether carpenter ants are inside the wood the woodpecker has been working. If yes, treat the colony before patching the holes. If no, you may just have woodpeckers attracted to the wood itself (cedar especially), and the fix is structural — replacing or covering the damaged area, deterring the birds.

Woodpecker deterrence is its own subject. Visual deterrents (reflective tape, predator silhouettes), tactile barriers (bird netting), and sound-based methods all work to varying degrees. A pest control company won’t typically handle this — woodpeckers are protected under the federal Migratory Bird Treaty Act and can’t be killed or captured without a permit. If the birds are the only problem, you’re looking for a wildlife control specialist or a handyman who installs deterrents, not pest control.

Get a Minnesota pro to confirm what’s inside the wood →

Candidate 2: Powderpost beetles

If the holes are tiny — pinhole-sized, between 1/32 and 1/8 of an inch in diameter — and they’re on indoor hardwood, you’re probably looking at powderpost beetles, not carpenter bees.

The full diagnostic for powderpost beetles is on the sawdust pillar, since the powder below the holes is the more reliable identifier than the holes themselves. Here’s the short version:

Holes are tiny. If you can fit anything bigger than a pencil tip into the hole, it’s not powderpost beetles.
They appear in indoor hardwood. Original oak floors in older Twin Cities homes, exposed hardwood beams, antique furniture. Almost never in pine framing or pressure-treated wood.
Multiple holes, often in a small area. Powderpost beetles emerge over multiple seasons, so you typically see a cluster develop over years.
Fine, talcum-powder-like dust below the holes. Powdery, no debris mixed in.

If your holes match this profile, see Sawdust piles in your house for the full diagnostic and treatment options.

Candidate 3: Actual carpenter bees (rare in Minnesota, but possible)

The eastern carpenter bee (Xylocopa virginica) is the species you’ve read about online. Where they’re established — most of the eastern US, much of Iowa and Wisconsin — they’re real homeowner pests. In Minnesota, they’re at the extreme edge of their range, and the U of M Bee Lab notes that it’s not even clear whether they have a self-sustaining population here or whether the few individuals documented were transported in by human means (lumber, furniture, etc.).

That said: a single male was photographed in Ramsey County in 2025. Climate is shifting, the species is expanding northward, and southern Minnesota — especially the metro and points southeast — is the part of the state where they’re most plausible. If you live in Bloomington, Edina, Eden Prairie, or south metro suburbs and you see what you genuinely think is a carpenter bee, your sighting could be one of the early ones. Worth confirming.

What actual carpenter bees look like and do

Large bumblebee-sized. Three-quarters of an inch to one inch long. The thorax has yellow fuzz; the abdomen is shiny black and mostly hairless (this is the key difference from bumble bees, which have fuzzy abdomens).
Holes are perfectly round, half an inch in diameter. Very clean, smooth bore. Goes in 1–2 inches, then turns 90 degrees and runs along the grain for 6–12 inches.
In unpainted, weathered softwood. Pine, cedar, redwood. They almost never drill into painted wood, pressure-treated wood, vinyl, or aluminum.
Yellow staining below the hole. Females excrete sticky yellow waste that runs down the wood from the entrance, sometimes leaving a fan-shaped stain. This staining is one of the more reliable identifiers, because no other pest produces it.
Coarse sawdust below the hole. Looks like fresh wood shavings, not powder.
Active April through September, with peak nest building in May and June.
Male carpenter bees are territorial but cannot sting. Females have stingers but rarely use them. The aggressive-looking dive-bombing you see is a male display.

This might be you if…

The hole is exactly half an inch in diameter, perfectly round, with smooth edges
You’ve seen a large black-and-yellow bee hovering near the hole
There’s yellow staining or coarse sawdust below
The wood is unpainted cedar, pine, or redwood
You’re in the south or east Twin Cities metro

What to do

If you’re confident it’s actually carpenter bees, treatment is straightforward but seasonal. Insecticidal dust applied directly into the hole at night kills the adult bee; the hole then needs to be sealed in late summer or fall (after offspring emerge) to prevent reuse. Painting or replacing the affected wood with painted or pressure-treated material is the long-term fix.

Because actual carpenter bee identification is rare enough in Minnesota that even pest professionals can be uncertain, getting a positive identification first matters more than rushing to treatment. A photo of the bee itself (not just the hole) sent to the U of M Extension’s Ask Extension service, or shown to a Twin Cities pest control technician, will resolve it quickly.

Get a Minnesota pro to confirm and treat →

Candidate 4: Old construction holes (the “not a pest” answer)

The least exciting answer, and often the right one in older homes: someone drilled the hole on purpose, decades ago, and you’re just noticing it now.

Wiring penetrations — small round holes where electrical wiring was run between studs, often visible in basements and attics, sometimes filled with caulk or wire wrap.
Plumbing penetrations — larger round holes where pipes pass through framing.
Old nail holes and screw holes — small, scattered, often filled with caulk and painted over but visible if the paint is thinning.
Pre-drilled vent holes — older homes sometimes have intentional ventilation holes in soffits, eaves, or attic framing.
Speaker wire / cable / phone line holes from previous owners’ setups.

This is probably you if…

The hole is a single isolated round hole, not a pattern
It’s in a logical location for utilities (near outlets, switches, pipes)
The hole shows signs of paint coverage or has been around a while (wood weathering matches the surrounding area)
The hole hasn’t changed or grown since you noticed it
You can see remnants of caulk, wire, or hardware in or near it

What to do

Nothing, generally. If the hole is an air-sealing or moisture concern, fill it with caulk, expanding foam, or wood putty depending on the location. If it’s purely cosmetic, paint over it.

What to do next

If you’ve worked through this and you have a tentative identification:

Woodpecker damage — Check for carpenter ants in the wood the bird was working before patching. If ants are present, treat first. If not, address the bird with deterrents.
Powderpost beetles — See our sawdust article for full guidance. Generally not an emergency.
Suspected carpenter bees — Get a positive ID before treating. In Minnesota, false positives are extremely common; many “carpenter bee holes” turn out to be woodpeckers.
Old construction — No pest action needed. Fill or paint as desired.

If you’re not sure — which is the normal state, because woodpecker holes and carpenter bee holes can look similar from the ground — a professional inspection is the fastest way to settle it. Most Twin Cities pest companies will identify the source on-site.

Typical Twin Cities pricing as of 2026:

Inspection only: Free to ~$100 (most reputable companies offer free inspections)
Carpenter bee treatment (if confirmed): $150–$400 for typical homes, often combined with sealing of holes
Carpenter ant treatment (if woodpeckers were after ants): $200–$500
Woodpecker deterrence: Not typically a pest control service; expect $200–$1,000 from a wildlife or handyman service depending on extent
Annual prevention/monitoring contract: $200–$400/year

Get a free inspection from a vetted Twin Cities pest pro

Twin Cities Pest ID partners with one local, licensed, fully-insured Twin Cities pest control operator who specializes in wood-damaging pests. We can connect you for a free inspection and species ID — no obligation to book treatment.

What you get:

Licensed Minnesota Department of Agriculture pest control technician

On-site species identification (carpenter bees, powderpost beetles, carpenter ants, plus assessment of woodpecker activity)

Inspection of the wood for hidden insect activity (the carpenter ant connection)

Clear quote, no high-pressure sales

Request a free inspection →

A note on what this site does (and doesn’t) do

Twin Cities Pest ID is a diagnostic resource for Minnesota homeowners. We help you figure out what you’re seeing so you can make informed decisions about treatment.

We’re not a pest control company ourselves. We don’t sell treatments or service contracts. When you contact us for an inspection referral, we connect you with one vetted local Twin Cities pest control operator we’ve evaluated for licensing, insurance, customer reviews, and pricing transparency. We receive a referral fee from them when their treatment is booked — but the referral fee doesn’t affect what you pay, and the operator we partner with doesn’t change based on the size of your problem.

We chose this model deliberately so we could write honestly. National pest control sites have an incentive to tell every homeowner with a round hole in their wood that it’s carpenter bees — that drives more inspection bookings. We don’t have that incentive, so we can tell you the truth: in Minnesota, those holes are usually woodpeckers or old construction, and most of the time you don’t need pest treatment at all.

If you’d rather investigate further on your own first, here are related guides:

Sawdust piles in your house — what’s causing them? — the powder-and-debris diagnostic
Do You Have Termites in Minnesota? — the swarmer-versus-ant identification
Carpenter Ants in Minnesota: identification and treatment — the woodpecker connection often points here

Last reviewed: May 2026. Sources: University of Minnesota Bee Lab — Xylocopa, University of Minnesota Extension — household insects, and direct consultation with licensed Twin Cities pest control operators.