New holes showing up on the outside of a house tend to get noticed fast, and understandably so — nobody wants to watch their siding turn into swiss cheese one peck at a time. The good news is that the pattern left behind is usually enough to identify the bird responsible without ever seeing it. In New Jersey, the two most likely suspects are a general woodpecker — Downy, Hairy, Red-bellied, or Pileated, all common across the state — or the yellow-bellied sapsucker, which migrates through and winters here. They behave differently, target different surfaces, and leave completely different evidence, so telling them apart is mostly a matter of looking closely at the holes themselves.
Why Woodpeckers Drill Into Houses
They drill for three distinct reasons, and each one leaves its own kind of mark. First, and most relevant if you're looking at a damaged wall, is foraging: one will chip away at siding or trim to reach carpenter ants or beetle larvae tunneling underneath, which means the bird itself is really just a symptom of an insect problem already living in that wood. Second is drumming — rapid, loud tapping meant to establish territory or attract a mate. No material gets removed during drumming, and birds often pick metal gutters, flashing, or chimney caps specifically because the noise carries further. Third is nest excavation, which produces a deeper, rounder cavity and typically happens in spring as pairs prepare to raise young. Since these three behaviors look so different up close, the holes themselves usually make it obvious which one you're dealing with.
Of the three, foraging damage is the one that deserves the most attention. If the holes are random and irregular, scattered loosely across a section of siding or trim rather than following any obvious pattern, that's usually the bird chasing insects it can hear or sense moving inside the wood. In other words, it found something worth digging for, and it's worth finding out what that something is before the damage spreads further.
Why The Sapsucker Behaves Differently
The yellow-bellied sapsucker plays by a different set of rules entirely. Rather than hunting insects hidden in wood, it drills small, uniform holes arranged in tidy horizontal rows — often called sap wells — into the bark of living trees, then returns to feed on the sap that seeps out along with any insects that get trapped in it. Because its whole feeding strategy depends on live sap flow, it has little reason to bother with house siding the way an insect-hunting cousin does, and damage to an actual structure from this bird is uncommon. When you do see its handiwork, the giveaway is that grid-like, evenly-spaced pattern — it looks almost deliberate, because in a sense, it is.
Woodpecker vs Sapsucker: Side-By-Side
Here's how the two compare on the details you're most likely to notice around the yard or on the house itself:
| Feature | Woodpecker (Downy, Hairy, Red-bellied, Pileated) | Yellow-Bellied Sapsucker |
|---|---|---|
| Hole Pattern | Random, irregular, scattered over an area | Neat horizontal rows of small, evenly-spaced holes |
| Why It Drills | Foraging for insects, drumming for territory/mates, or excavating a nest cavity | Feeding on tree sap and insects trapped in it |
| Appearance | Varies by species — black-and-white patterning is common, Pileated has a bold red crest and is crow-sized | Black-and-white body with a pale yellow-tinged belly and a red forehead patch |
| When Active in NJ | Year-round residents; drumming peaks in spring | Migrates through in spring and fall; some winter over |
| Damage Type | Can damage siding, trim, and gutters — sometimes structural if foraging continues | Damages live tree bark; rarely touches house siding |
| What Attracts It | Insects already inside the wood, loud resonant surfaces for drumming, sheltered nesting spots | Living, sap-producing trees near the property |
What To Actually Do About It
Since both birds fall under the Migratory Bird Treaty Act, trapping, harming, or otherwise harassing either one isn't legal — and honestly, it isn't the right approach anyway, since it does nothing to address why the bird showed up in the first place. If you've got a sapsucker working a tree trunk, the honest answer is usually to leave it be; the tree may show cosmetic sap-well scarring over time, but real harm to a healthy tree is rare. Its counterpart working your siding instead is the case that actually calls for action, and specifically for figuring out what drew it there. Visual deterrents, reflective tape, and hanging decoys can discourage repeat visits, but if the bird keeps coming back to the same spot, that persistence itself is a clue: something under that siding is worth its time, and that something is very likely a pest, not the wood itself.
At that point, the smartest move is having someone check both ends of the problem at once. Our bird control services handle that side of it safely and legally, while our pest exclusion services track down whatever insect activity might be luring the bird back to the same board day after day. Since the two often go hand in hand, a full home pest-proofing visit can close off the gaps and food sources drawing pests into your siding in the first place, cutting off its reason to keep coming back. And if you're already dealing with pests elsewhere on the property, it's worth bundling the visit — whether that means ant control in Oakland or rodent control in New Milford, we can take a look at the siding damage while we're already on-site. Catching it early usually means a simple fix instead of a repair job down the line.