Sapsuckers are unique woodpeckers that drill sap wells into trees in order to drink the sap that flows out. But do they actually drink this sap? The short answer is yes, sapsuckers do consume sap as part of their diet.
Sapsucker Behavior
Sapsuckers, also known as yellow-bellied sapsuckers, are medium-sized woodpeckers found throughout forests in North America. They are known for their unique habit of drilling rows of small holes, called sap wells, into the bark of trees. The sap wells damage the inner bark and cambium layer of the tree, causing sap to ooze out of the holes. The sapsuckers then return to feed on this sap, as well as trap insects that are also attracted to the sap.
There are four species of sapsuckers in North America:
- Yellow-bellied Sapsucker
- Red-naped Sapsucker
- Red-breasted Sapsucker
- Williamson’s Sapsucker
While all sapsucker species share this sap-feeding habit, the yellow-bellied sapsucker is most strongly associated with drilling sap wells and consuming tree sap. Their tongues even have adaptations like hair-like projections to help them lap up sap.
Sapsucker Diet
Tree sap forms a major part of the sapsucker’s diet, particularly during winter and early spring when other food sources are scarce. Sapsuckers drill their sap wells in a wide variety of tree species, with birch, maple, pine, and fruit trees being some of their favorites. The sap they harvest provides an important source of sugar and carbohydrates.
In addition to tree sap, sapsuckers also feed on cambium scraped from the sap wells, as well as insects harvested from the sap flows or from under bark. Their diet changes throughout the seasons with the availability of food. Here is an overview of what makes up the sapsucker diet by season:
| Season | Diet |
|---|---|
| Winter | Tree sap, insects in sap wells |
| Spring | Increasing amounts of cambium, insects, fruit |
| Summer | Cambium, fruit, insects |
| Fall | Insects, sap, fruit, seeds |
As you can see, tree sap provides an important food source for sapsuckers throughout the year, especially in the winter when other foods are scarce. Even during summer when they consume more cambium and fruit, sap helps provide sugars that fuel their active lifestyle.
Sap Consumption
Research has confirmed that sapsuckers do indeed drink and digest the sap they harvest. Sapsuckers have specialized lingual papillae and brush-like features on their tongue that help them lap up sap. They also have adaptations in their digestive system like an enlarged liver that helps them metabolize and process the sugar-rich sap.
Scientists have analyzed the stomach contents of sapsuckers and found evidence of sap intake. For example, one study of yellow-bellied sapsuckers in New York found that tree sap made up over 50% of their stomach content in the early spring. Sucrose, a type of sugar found in sap, was present in their stomachs year-round.
Researchers have also conducted feeding trials in captivity by providing sapsuckers with artificial nectar or sap formulas. The birds readily consumed these sugar-rich solutions, confirming their taste and appetite for sap.
So while sapsuckers eat a varied diet, particularly in warmer months, the evidence clearly shows that they directly consume and can digest significant quantities of tree sap. The sap provides an important source of carbohydrates and energy for these uniquely adapted woodpeckers.
Impact on Trees
The sap feeding habit does take a toll on trees over time. A single sapsucker can drill up to 1000 or more sap wells in a breeding season. Repeated drilling and sap bleeding damages the inner bark, which can eventually kill branches or entire trees if sap wells remain open.
However, healthy trees with active sap flows can usually withstand sapsucker damage. The holes tend to heal over with callous tissue after some weeks or months. So while sapsuckers do negatively impact individual trees, they rarely cause widespread tree death. Their habitat engineering also provides food and shelter for other species.
Landowners can protect high-value ornamental or fruit trees by wrapping hardware cloth or wire screen around the trunks to prevent sapsuckers from drilling. But in general, the species plays an important ecological role in the forest food web.
Conclusion
Sapsuckers are the true sap-feeding specialists among North American woodpeckers. Their distinctive habit of drilling orderly rows of sap wells provides these birds with an important source of sustenance, especially in winter and early spring. While sapsuckers eat insects and other foods as well, research clearly demonstrates that they directly and regularly consume sap as a nutritious component of their diet. The sapsucker’s specialized adaptations allow it to harvest and digest tree sap, affirming that yes, sapsuckers do drink sap.
