Sapsuckers are woodpeckers that drill holes into tree trunks to feed on the sap that flows out. This feeding behavior can cause significant damage to trees over time. Sapsucker damage is recognizable by the unique pattern of small holes drilled in horizontal and vertical rows on tree trunks. If you see neat rows of quarter-inch holes in the bark of your trees, you likely have sapsuckers visiting your yard. Read on to learn more about identifying and dealing with sapsucker damage.
What are sapsuckers?
Sapsuckers are medium-sized woodpeckers that drill sap wells into the bark of living trees. There are four species of sapsuckers in North America:
- Yellow-bellied Sapsucker
- Red-naped Sapsucker
- Red-breasted Sapsucker
- Williamson’s Sapsucker
These birds have distinctive black and white plumage accented with splashes of red or yellow on their head and throat. Sapsuckers drill orderly rows of small holes into the bark of trees to access the sap underneath. As the sap oozes out, it forms sweet deposits that attract insects for the birds to eat. Sapsuckers also lap up the sap directly with their brush-tipped tongues.
Why do sapsuckers drill into trees?
Sapsuckers drill holes into tree bark for two main reasons:
- To feed on the sap that flows out of the holes
- To attract insects drawn to the sap
These birds have a whole repertoire of sap-feeding behaviors. They use their beaks to hammer neat rows of holes into trunks, branches, and even woody vines. Sapsuckers also enlarge old holes to renew sap flow. The sap that oozes out hardens into sugary deposits that attract insects. Sapsuckers use their specialized tongues to lap up both the sap and insects gathered on the tree.
What trees do sapsuckers prefer?
Sapsuckers target certain tree species more than others. Their favorite sap trees include:
- Birch
- Maple
- Willow
- Poplar
- Ash
- Pine
- Spruce
- Fruit trees like apple, plum, and cherry
These tree species have sap that appeals to sapsuckers’ taste. The birds also seem to prefer trees with relatively smooth, thin bark that makes sap access easier. However, sapsuckers will drill any healthy tree in their range, so no species is completely exempt.
Identifying Sapsucker Damage
Part of controlling sapsucker damage involves learning how to identify it. There are some key signs that point to sapsuckers as the culprits:
Neat rows of small holes
The most distinctive indicator of sapsucker damage is the orderly rows of quarter-inch holes they drill. Sapsuckers tap out long horizontal rows of holes, then neatly start another row right above or below it. The holes are evenly spaced about 1-2 inches apart. You might also see vertical columns of holes along the trunk. The holes look very uniform and organized compared to other woodpecker drumming.
Sap flow
Active sap wells will have a ring of fresh, moist sap around the holes or even dripping down the bark. Older holes may be ringed with dried, crystallized sap deposits. The sap oozes out from the damage to the inner bark and sapwood where the bird has fed. This sap flow is a sure sign that sapsuckers have recently been drilling.
Squarish or rectangular holes
Sapsucker holes tend to be neat and rectangular shaped. Their holes are typically about 1/4 inch across. This squarish hole shape comes from their specialized drilling method. Other woodpeckers make rounder holes when drumming on trees. If the holes have distinct corners, their geometry points to sapsuckers.
Shallow holes
Sapsuckers only drill into the sapwood a couple inches at most. Their holes do not penetrate deep into the trunk like other woodpecker holes. This is because they are just tapping into the thin sap layer underneath the bark instead of boring for insects. The shallow holes help distinguish sapsucker damage.
Location on trunk
Sapsuckers drill sap wells in areas with thin, smooth bark, often on younger trunks and branches. Oftentimes the holes encircle the trunk in bands. Damage is usually concentrated between ground level and lower branches away from the crown. The birds favor drilling on the sunny side of young trees.
Appearance of Damage by Tree Part
The location of sapsucker damage provides more clues for identification. Different parts of the tree display characteristic signs:
Trunk
The trunk is the most common location for sap wells. Horizontal rows of holes bored into the sapwood formdistinct bands around the trunk. These damage rings may encircle the entire girth or only part. You’ll also see vertical columns of holes. Bark below older holes is sometimes injured.
Branches
Sapsuckers drill holes in a branching pattern along smaller limbs. The rows follow the contour of the branch and may form complete loops around it. The holes patterning along smaller branches helps distinguish sapsucker damage.
Twigs and vines
Twigs and woody vines are also not exempt from sapsucker activity. You may find their characteristic sap wells drilled along the length of twigs or winding around vines. This shows their willingness to tap anything with sap.
Leaves and roots
Leaves, roots, and the upper trunk are rarely touched. Sapsuckers stick to sap-bearing woody parts lower on the tree. Any damage to foliage or at the soil line is likely caused by other factors.
| Tree Part | Typical Sapsucker Damage |
|---|---|
| Trunk | Horizontal and vertical rows of holes in sapwood forming bands around trunk |
| Branches | Holes drilled in branching pattern along smaller limbs |
| Twigs and vines | Sap wells winding around length of twigs and vines |
| Leaves and roots | No damage |
Damage Differences by Species
While all sapsuckers cause similar damage patterns, the appearance may vary slightly based on the specific woodpecker species:
Yellow-bellied sapsucker
Yellow-bellied sapsuckers make very neat, rectangular holes in horizontal and vertical rows. They drill very orderly sap wells compared to other species. The holes are small and evenly spaced. Damage is restricted to lower trunk and branches.
Red-naped sapsucker
Red-naped sapsuckers drill holes in a less orderly fashion than yellow-bellied sapsuckers. Their holes may be more unevenly spaced and less consistent in size. Damage extends higher up the trunk.
Red-breasted sapsucker
Red-breasted sapsuckers drill small but deep holes that penetrate deeper into wood. Their holes are also less organized into straight rows. Damage appears messier overall.
Williamson’s sapsucker
Williamson’s sapsuckers make very clean, distinctive holes in neat rows, though less uniform than yellow-bellied sapsuckers. Damage is mostly low on the tree but may reach over 15 feet up the trunk.
Seasonal Differences
Sapsucker damage patterns change across the seasons:
Spring
In spring, sapsuckers drill fresh sap wells for the growing season. New holes appear as the birds establish feeding territory. Sap flow is at its heaviest during spring.
Summer
Sapsuckers maintain and enlarge old holes through the summer. Drilling damage is focused on keeping sap flowing from existing wells. Sap production decreases, so new holes taper off.
Fall
Sapsuckers drill new holes in the fall to access sap before winter dormancy. New damage increases again as they prepare for colder months. Sap flow slows as trees prepare for winter.
Winter
In winter, sap flow stops completely. Sapsuckers abandon trees and do not drill new holes during winter. Damage is limited until spring. Existing holes callous over.
| Season | Sapsucker Damage Pattern |
|---|---|
| Spring | Fresh sap wells drilled; heavy sap flow |
| Summer | Enlarging existing holes; decreased sap flow |
| Fall | More new holes drilled; sap flow slowing |
| Winter | No new holes; sap flow stopped |
Damage Differences by Tree Health
The appearance and extent of sapsucker damage also depends on the condition of the tree:
Healthy trees
Sapsuckers prefer to feed on vigorous, healthy trees with an active sap flow. Damage to healthy trees looks very neat and orderly. The holes penetrate deep into fresh sapwood. Sap pours out of the wells.
Stressed trees
Stressed or declining trees with less vigorous sap flow show more scattered damage. The holes appear messier as the birds move around seeking sap. Wells are shallower in dried out sapwood. Little sap flow oozes out.
Diseased trees
Diseased trees exhibit limited sapsucker damage since sap production is decreased. Any drilling is shallow and disorganized. Very little sap comes out of the limited holes. Sapsucker damage is reduced overall.
Dead trees
Sapsuckers do not feed on dead or dying trees with no sap flow. No fresh holes will appear on dead trees. Existing holes dry out and callous over. Damage is limited to the final stages of decline.
| Tree Health | Sapsucker Damage |
|---|---|
| Healthy | Neat, orderly holes in fresh sapwood with heavy sap flow |
| Stressed | Scattered, shallow holes with reduced sap |
| Diseased | Few, very shallow, scattered holes with little sap |
| Dead | No new holes, existing holes dried out |
Estimating Age of Damage
You can also make educated guesses about how fresh sapsucker damage is based on appearance:
Recent holes
Holes made within the past year will appear very clean, white, and fresh. The wood surrounding the holes will not be darkened or stained. Oozing sap and moist rings around holes signal fresh damage.
Older holes
Holes more than a year old start to scar over and discolor. The wood around older holes turns gray or black over time. Healed holes may have callused tissue around the edges. No sap flow indicates the damage is not fresh.
Enlarged holes
Enlarged holes with sap flow indicate active feeding. Sapsuckers maintain old holes by reopening and enlarging them. The mixed hole sizes show a history of repeated feeding.
Sealed holes
Completely sealed, callused holes with no sap oozing out are often many years old. The tree has grown over very old damage. Distorted, stained tissue covers ancient sap wells.
| Hole Appearance | Age of Damage |
|---|---|
| Clean, white, fresh holes with sap flow | Recent – within past year |
| Discolored, callused holes with no sap | Older – 1+ years ago |
| Mixed enlarged and smaller holes | Active repeated feeding |
| Completely sealed, distorted holes | Many years old |
Comparing to Other Damage
Sapsucker holes have a distinct appearance different from other common types of tree damage:
Woodpecker drumming
– Drumming damage from other woodpeckers consists of randomly placed, shallow holes where birds have hammered on trunks and branches.
– The holes do not form neat rows and columns like sapsucker holes.
– Drumming holes are rounder due to the pecking motion. Sapsucker holes are more rectangular.
Squirrel damage
– Squirrels chew away rough chunks of bark to access sap. Damage looks ragged, not neatly drilled.
– May see bite marks and claw marks from squirrels.
– Squirrels access trees from all directions, not in orderly rows.
Beetle holes
– Beetles bore very small, round holes in random scattering patterns, not neat rows.
– Beetle holes contain boring dust and frass pushed out by larvae.
– Damage often follows trails in the inner bark eaten by beetle larvae.
Cankers
– Canker fungal infections create sunken, swollen areas scattered on bark surface.
– Edges may look torn or ragged rather than neatly drilled.
– Discolored, dead tissue surrounds canker margins.
Bird pecks
– Miscellaneous little bird pecks look like small pits or chips scattered randomly over the bark.
– Lack any pattern or consistency compared to sapsucker holes.
– Created by variety of birds, not just woodpeckers.
Conclusion
In summary, identifying sapsucker damage requires reading the clues left by these unusual birds. Look for their telltale sap wells drilled in recognizable patterns on tree trunks and branches. The neat rows of quarter-inch rectangular holes oozing sap give sapsuckers away. Factors like tree health, season, and hole appearance provide more insight into the age and source of the damage. Distinguishing sapsucker holes from other types of defects takes some woodpecker expertise. But with practice, anyone can learn how to decode the distinguishing signs these unique woodpeckers leave behind.
