Pileated woodpecker holes are distinctive rectangular excavations, often a foot or more long, carved deep into the wood of dead or decaying trees. They’re unlike anything other North American woodpeckers produce, and if you’ve found large, squared-off cavities in a tree on your property or in the woods, a pileated woodpecker is almost certainly responsible. These birds create several different types of holes depending on whether they’re feeding, nesting, or roosting, and each type has a recognizable shape, size, and location.
How to Identify Pileated Woodpecker Holes
The signature giveaway is the shape. While most woodpeckers drill small, round holes, pileated woodpeckers carve large square to rectangular openings or long trough-like furrows that can measure over one meter in length. You’ll often find large piles of thumb-length wood chips scattered at the base of the tree. The excavated areas typically show a ring of pale, bare sapwood around the opening, contrasting sharply with the darker intact bark surrounding it.
These holes can be so broad and deep that they sometimes cause small trees to break in half. The birds target trees at least 25 centimeters in diameter, though they prefer trunks wider than 40 centimeters. If you’re looking at a tree with massive rectangular gouges and a heap of coarse chips on the ground, you’re looking at pileated woodpecker work.
Three Types of Holes and How They Differ
Feeding Excavations
Feeding holes are the most visible and dramatic. They’re irregular in shape, often rectangular or trough-like, and extend only 5 to 20 centimeters into the wood. Their shallow depth means the exposed wood inside looks lighter in color than deeper cavities. These excavations follow the tunnels of carpenter ants, the bird’s primary food source, so they tend to zigzag or branch as the bird traces the colony through the heartwood. A single tree can have multiple feeding holes scattered across the trunk.
Nesting Cavities
Nesting holes look quite different. They’re round or teardrop-shaped, roughly 9 centimeters wide and 12 centimeters tall, leading to an interior cavity that can reach 75 centimeters deep. There’s typically only one nesting hole per tree. Both the male and female excavate a new nest cavity each year, usually in a dead or decaying tree. They don’t add any lining material; the only cushioning for eggs is leftover wood chips from the excavation itself. The oblong entrance sets these apart from the circular holes of smaller woodpecker species.
Roosting Cavities
Roosting holes, used for sleeping and shelter, are oval-shaped and measure 7.5 to 10 centimeters wide by 10 to 12.5 centimeters high. What’s remarkable is the interior: roosting cavities can extend up to 4.5 meters in length inside the tree. These are deep, vertical chambers that provide insulation and protection from predators and weather.
Which Trees Get Targeted
Pileated woodpeckers don’t excavate holes in healthy, sound wood. Their feeding damage is actually a reliable indicator that a tree already has an insect infestation or internal decay. Trees chosen for feeding are infested with beetles or carpenter ants and are usually old-growth or dead. Snags, stumps, and logs lying on the forest floor are all fair game.
For nesting and roosting, the birds almost always select trees that have existing columns of wood decay caused by bracket fungi. In the Pacific Northwest, Douglas fir is a preferred nest and roost tree. The key pattern is that pileated woodpeckers seek out soft, weakened wood. If a pileated woodpecker is hammering into one of your trees, the tree likely had a fungal or insect problem before the bird arrived.
Do the Holes Kill Trees?
Woodpecker holes themselves don’t kill trees. The excavation does create open wounds, though, which make the tree more vulnerable to insects and disease entering through the exposed wood. Since pileated woodpeckers overwhelmingly target trees that are already dead, dying, or decayed internally, the holes are more a symptom of existing decline than the cause of it. In rare cases where the bird works extensively on a smaller living tree, the structural damage can be severe enough that the tree snaps. But a large, otherwise healthy tree with a single set of feeding marks will generally compartmentalize the wound and continue growing.
Why These Holes Matter for Wildlife
Pileated woodpeckers are considered keystone habitat modifiers because so many other species depend on the cavities they create. A USDA Forest Service report documented over 20 species in the Pacific Northwest alone that nest or roost in old pileated woodpecker excavations. The list is strikingly diverse: wood ducks, hooded mergansers, and buffleheads use them as nest sites near water. American kestrels, several owl species (including boreal owls, northern saw-whet owls, and western screech-owls), and Vaux’s swifts move into abandoned cavities. Among mammals, northern flying squirrels, American martens, fishers, and multiple bat species rely on these holes for shelter.
No other woodpecker in North America creates cavities large enough for many of these animals. Without pileated woodpeckers continuously excavating new holes each breeding season, the supply of large tree cavities in a forest would shrink dramatically, and the populations of all these secondary users would decline with it.
Protecting Your Trees
If a pileated woodpecker is working on a tree in your yard, the first thing to understand is that the bird is protected under the Migratory Bird Treaty Act. It’s illegal to kill, capture, or harass pileated woodpeckers without a permit from the U.S. Fish and Wildlife Service. If a nest is already active, you’ll need to wait until the young leave permanently, typically by midsummer, before taking any action.
Physical barriers are the most effective deterrent. Bird netting stretched taut from the eaves or upper trunk down over the affected area blocks access reliably. For ornamental trees being damaged by sapsuckers (a related issue), wrapping the trunk in burlap or heavy fabric can help. Visual scare devices like owl decoys, spinners, and windsocks have inconsistent results. Playing recorded woodpecker distress calls followed by raptor calls sometimes works as a sound deterrent, but results vary.
Avoid sticky gels or tactile repellents. These substances can coat feathers and impair the bird’s ability to fly or regulate body temperature. If a woodpecker has already created holes, fill and paint them promptly to discourage the bird from returning to the same spot and to reduce the chance of decay organisms entering the wound.
The most practical first step, though, is to assess the tree itself. A pileated woodpecker drilling feeding holes is telling you that carpenter ants or wood-boring beetles are already inside. Addressing the insect infestation, or recognizing that the tree may be in decline, is often more important than deterring the bird.