Neat Rows of Holes in Your Tree? That's a Sapsucker

By Margaret Ellison, Tree & Shrub Health. Last updated: July 9, 2026.

Here is what usually prompts the panicked photo to an arborist:

• Tidy horizontal (or vertical) rows of small, shallow holes
• Holes so evenly spaced they look drilled by hand, often in a grid
• Fresh sap weeping from the wells, sometimes with insects stuck in it
• Wasps, ants, or even hummingbirds visiting the sticky bark
• The same tree hit again in the same band, year after year

What makes neat rows of holes in tree bark?

A yellow-bellied sapsucker (Sphyrapicus varius), a woodpecker that feeds on sap rather than boring insects. It drills shallow "sap wells" in orderly rows, then returns to lick up the sap that pools there and eat any bugs the sap traps. The pattern is the whole tell: a bird drills in lines and grids, and an insect does not.

The bird is not fussy about its host. The Cornell Lab of Ornithology has documented sap wells in more than 1,000 species of trees and woody plants, and the Missouri Department of Conservation describes the marks plainly as "small, often evenly and closely spaced holes." University of Maryland Extension puts a number on them: sapsuckers drill rows of 1/4 to 3/8 inch closely spaced holes in otherwise healthy bark.

One more fact settles the identification: this is a migratory bird. The yellow-bellied sapsucker is the only fully migratory woodpecker in eastern North America, passing through the Rochester area in spring and fall, which is exactly when homeowners notice fresh drilling. If the rows sit alongside other trunk symptoms you are trying to read, our guide to bark splitting and cracking on Rochester trees covers what those other marks mean.

How do I tell sapsucker holes from borer holes?

The layout gives it away. Sapsucker wells are shallow, uniform, and lined up in rows or a neat grid, usually wrapping a section of trunk or a large limb, often with sap glistening at the surface. A wood-boring insect leaves a very different scene: scattered, random holes, dry frass or sawdust, and tunnels under the bark rather than sap on top of it.

The clearest contrast is with emerald ash borer, the pest most Monroe County homeowners fear when they see holes. Emerald ash borer leaves distinctive D-shaped exit holes placed at random and winding S-shaped galleries packed with sawdust just under the bark, nothing like a sapsucker's tidy rows. Our full guide to emerald ash borer in Monroe County walks through those signs. When the holes are random and dry rather than lined up and wet, or when the canopy is thinning from the top down, you are likely looking at a borer or a deeper problem, and our why is my tree sick diagnostic guide helps you sort a symptom from its cause.

Is sapsucker damage harmful to a tree?

Usually not much, on a healthy, established tree. As the Missouri Department of Conservation puts it, "in most cases, these woodpeckers do not cause serious damage to mature trees." A vigorous tree seals its wells and moves on.

The risk is real, though, in two situations. First, the wounds are open doors. University of Maryland Extension notes the feeding holes "may also serve as entrances for diseases and wood decaying organisms," and warns that "occasionally limb and trunk girdling may kill the tree." Second, the birds prefer trees that are already struggling. Paul Hetzler, an ISA Certified Arborist writing for Cornell's ForestConnect program, explains that a vigorous, vital tree produces "noxious compounds at feeding sites in an effort to repel insects," while a weakened tree "cannot mount such a defense and is thus 'tastier.'" That is why concentrated drilling matters: Hetzler notes a single ring of sap wells can chip out most of the cambium in that band, disrupting the vascular system across roughly 70 to 80 percent of the trunk. On a small tree, or on the same favored specimen hit season after season, that adds up.

So the honest answer is: monitor a few rows on a big, healthy maple, and take a densely girdled band on a young or prized tree seriously.

Which trees do sapsuckers target in Rochester?

Species with sweet, sugary sap top the list, which in Upstate New York means birches (paper and yellow birch), sugar and red maple, hickory, and often pines and spruces. Ornamental and fruit trees, including crabapple and apple, get worked over too. Because the birds return to a well they like, a single tree in a yard can carry years of neatly stacked rows while its neighbors are untouched.

Two things concentrate the damage locally. Sapsuckers move through with the migration, so the drilling tends to arrive in pulses rather than year-round. And, per Hetzler's point above, they lean toward trees that are already stressed by drought, compacted soil, or root trouble. That makes a favored, repeatedly drilled tree worth a second look: the bird may be telling you the tree was under strain before it ever showed up.

How do you protect a favored tree from sapsuckers?

Start with the fact that shapes every option: the yellow-bellied sapsucker is federally protected. Per the Internet Center for Wildlife Damage Management, "all species of woodpeckers are classified as migratory non-game birds and are protected by the Federal Migratory Bird Treaty Act," so lethal control is off the table without a federal permit. Deterrence is the game.

What actually works on a prized tree:

• Wrap the drilled band. University of Maryland Extension recommends barriers of 1/4 inch hardware cloth, plastic mesh, or burlap around the injured area so the bird cannot land and drill. Remove burlap once the birds have moved on, since leaving fabric on the trunk can trap moisture and invite the very insects and decay you are trying to prevent.
• Add a sticky or visual deterrent. A tacky trunk product (sold as a bird repellent) makes the surface hard to grip, and reflective scare devices, such as flashing tape or spinning reflectors hung near the wells, break up the bird's routine.
• Keep the tree vigorous. Because sapsuckers favor stressed trees, deep watering in dry spells, proper mulching, and relieving soil compaction do double duty: a healthier tree is both a less appealing target and better able to seal the wounds.
• Do not wrap loosely with non-stretch cord or leave a wrap on for years. A tight, forgotten wrap girdles the tree itself.

FAQ

Will the tree heal the holes on its own?

A healthy tree walls off and closes small sap wells over time, and a few rows on a large, vigorous tree rarely need any intervention. The concern is not a single season of holes but repeated drilling in the same band year after year, which can girdle the area and let decay set in before the tree can seal it.

Can sapsuckers actually kill a tree?

Rarely, but yes in the wrong circumstances. Most mature trees shrug off the feeding, yet University of Maryland Extension notes that occasional limb and trunk girdling can kill a tree, and small or already stressed trees are the most vulnerable. A tightly stacked ring of wells that wraps most of the trunk is the pattern to watch.

Is it legal to harm sapsuckers in New York?

No. The yellow-bellied sapsucker is a migratory bird protected by the federal Migratory Bird Treaty Act, so it is illegal to kill, capture, or harm one without a federal permit. That is why the recommended response is always non-lethal: wrapping, sticky deterrents, and scare devices rather than any attempt to remove the bird.

Does the sap from the wells attract insects or disease?

It can. The oozing sap draws ants, wasps, and other insects, and the open wounds can serve as entry points for wood-decaying fungi and bacteria. That is why wrapping the area during feeding periods, and removing the wrap afterward, helps limit the secondary problems more than the original holes.

Sources

• Monster Tree Service of Rochester
• University of Maryland Extension: Woodpecker and Sapsucker Damage on Trees
• Cornell Lab of Ornithology (All About Birds): Yellow-bellied Sapsucker
• Missouri Department of Conservation: Yellow-bellied Sapsucker
• Cornell ForestConnect: Sapsucker Damage Indicates Stressed Trees (Paul Hetzler, ISA Certified Arborist)
• Internet Center for Wildlife Damage Management: Woodpeckers