The Life Style of Yellow-bellied Sapsuckers

Sapsuckers (Piciformes or Picidae) are a group of woodpeckers that specialize in feeding on tree sap. They do this by drilling holes in trees, which in turn causes sap to flow out. Theses woodpeckers then eat the sugary liquid contained in these sap wells. They even have a brush-tipped tongue for lapping up sap.

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Yellow-bellied Sapsuckers (Sphyrapicus varius) are attractive birds with a barred, mottled black-and-white pattern. Their striped faces include a black band across their eyes. Both sexes also show a long vertical white patch along the sides of their closed wings. Along with this, Yellow-bellied Sapsuckers have an obvious red forehead. Males, however, also sport a red throat whereas the female’s throat is white. Although named for having a yellow belly, this can be deceptive, as the yellow can be very pale or can sometimes be completely absent.

Do Yellow-bellied Sapsuckers Only Eat Sap?

I would like to say that it is all in the name, but that isn’t the case. While it is true that Yellow-bellied Sapsuckers depend on sap, they also dine on a variety of other items. In addition to sap, Yellow-bellied Sapsuckers eat fruit, spiders, and insects (mainly ants). You may see them moving up and down trees, using their stiff tail feathers for support. Pausing, they examine the bark for insects hiding underneath. This is especially productive when gathering ants. At times, they may also eat flying insects, catching them right out of the air.

When drilling holes, Yellow-bellied Sapsuckers generally place the new holes in vertical or horizontal lines from the old holes. Furthermore, they drill two types, either round or rectangular.

The round holes are deeper than the rectangular holes. These are cut deep into the trees, but are not enlarged. They then simply put their beaks into the holes to lap up the sap. This type of hole is drilled in the spring in order to feed on the sap moving up to the branches.

The shallower, more rectangular holes are generally carved out after the trees leaf out. These holes collect sap moving down from the leaves. These shallower holes must be maintained in order to keep the sap continually flowing. The sapsucker will lick the sap from these holes, along with also feeding on the cambium of trees. This is a thin layer of living cells in a tree that produces new wood and bark. These sap pools will also attract insects, which the sapsucker may in turn eat.

Yellow-bellied Sapsuckers are Beneficial to Nature

Yellow-bellied Sapsuckers winter in the southeastern U.S. and down through Central America. In the early spring, they migrate north at a time when the “sap is running.” Around the same time, Ruby-throated Hummingbirds also make their way north. As the Yellow-bellieds feed, the fresh holes they create along the way not only benefit sapsuckers, but also hummingbirds. Tree sap is similar in sugar content to the nectar hummingbirds rely on from flowers. Because of this, Ruby-throated Hummingbirds also feed from these wells.

Studies show that in some cases Ruby-throated Hummingbirds are so dependent on sapsuckers that they will sometimes nest close to active sap wells. Ruby-throated Hummingbirds have even been seen following sapsuckers as the woodpeckers fly from one sap tree to another. Besides Ruby-throated, Rufous and Anna’s Hummingbirds also benefit from the Yellow-bellied’s excavations. This is especially important in the early spring, when many of the flowers the birds depend on have not yet bloomed.

However, Yellow-bellied Sapsuckers and Hummingbirds aren’t the only ones who enjoy feeding on sap wells. Other birds such as Ruby-crowned Kinglets, nuthatches, and chickadees, as well as bats, squirrels, moths, bees, wasps, and porcupines also take advantage of these sap wells.

Choosing and Drilling a Nest

Yellow-bellied Sapsuckers are cavity nesters. Males arrive about a week ahead of females. As a result, the male usually chooses the tree. He announces and establishes his territory by drumming on trees as well as sometimes other objects. He also does most of the work of excavating, although at times the female may help. This work may take 2 or 3 weeks to complete. When choosing a tree, the male will often look for one that is infected with a fungus which causes the tree’s heartwood to decay. This in turn makes his work of excavating easier.

The nest cavity may be up to 10 inches deep, however the entrance hole is quite small, only about 2.5 inches in diameter. No further work is needed. No lining is added, and the eggs are simply laid on wood chips present from the excavation.

Sapsucker’s nest cavities may be used for a number of years. Cornell’s All About Birds reports that these nest holes may be used for up to 7 years. Even when not reused, old cavities may be used by other cavity nesting birds such as the Black-capped Chickadee and Tree Swallows.

Courtship and Parental Duties

During courtship, sapsuckers will chase each other around trees. Landing on a tree branch they will face each other, raising their bills and tails. They will fluff out crown feathers and move their heads from side to side. They will also do this facing off and head swinging as an aggressive move with sapsuckers of the same sex.

Sapsucker mates stay together throughout the nesting season. The female lays 4 – 6 eggs, which both parents take turns incubating for around 2 weeks. Thereafter, the parents will work jointly to raise the chicks, feeding them insects, which are dipped in sap for extra nutrition. The chicks fledge in about a month, with the parents often encouraging them with food.

Yellow-bellied Sapsuckers will often reunite in future breeding seasons, though not always. As with many other birds, researchers believe their loyalty is probably not the mate, but rather it is the nesting area, including the nest hole that attracts them.

Do Yellow-bellied Sapsuckers Damage Trees?

Yellow-bellied Sapsuckers are beneficial to a number of other animals. Moreover, they can help control invasive insects that are destructive to forests.

In most cases, the holes do not kill trees. Typically healthy trees will quickly seal off the holes. However, it is possible that at times the damage may kill trees. This happens when they severely girdle the trunk. As a result, their drilled holes may cut off the needed flow of water and nutrients in the cambium layer of the tree. However, the University of Arkansas’s Division of Agriculture Research reports that this happens in only about 1-2 percent of the time.

In cases where this seems to be happening near homes, many different things have been tried. These include wrapping the injured part of the trees with barriers of 1/4 inch hardware cloth, plastic mesh, aluminum flashing, or burlap in order to discourage further damage. Others have tried hanging shiny objects such as CDs to twirl in the breeze. However, the success rate of these methods brings mixed results.

Visiting the Buffalo Bill Center of the West

If you are traveling to or through Cody, the Buffalo Bill Center of the West is a must stop. It is a world-class center with 5 museums and a research library located under one roof. Each museum focuses on a different aspect of the west.

Be sure to take a slow walk through the Draper Natural History Museum where you will learn about wildlife, plants, and other natural history subjects.
https://centerofthewest.org/our-museums/yellowstone/

You can even complete a scavenger hunt while you walk through its various ecosystems. Look carefully for the hidden mounts displayed in their natural environments. And don’t forget to look up into trees. If you are observant you will find a Yellow-bellied Sapsucker taking flight from a tree.

To hear and see a Yellow-bellied Sapsucker in action watch this 1-minute video from the Cornell Lab of Ornithology: https://www.youtube.com/watch?v=fgO53943xrg

Photos

Note: Adobe Stock Photographs used through a license paid for by the Buffalo Bill Center of the West.

Male Yellow-bellied Sapsucker on a tree girdled by drillings, by Dennis Donohue

Male Yellow-bellied Sapsucker by Terry Lorenc, Attribution-NonCommercial-NoDerivs 2.0 Generic license

Yellow-bellied Sapsucker feeding on Cedar Berries by Stan Lupo, Attribution-NonCommercial-NoDerivs 2.0 Generic license

Birch Tree damage showing round and rectangular holes, by Lganz

Female Yellow-bellied feeding from a small round hole by Jeff Bryant, Attribution-NonCommercial 2.0 Generic License

Sap wells by ondreickka

Male at a nesting hole by Keith Williams, Attribution-NonCommercial 2.0 Generic license

Nesting hole with male and female by Richard Bonnett, Attribution-Noncommercial 2.0 Generic license

Male on girdled tree showing both round and rectangular holes, by John Mangold, Attribution-NonCommercial-NoDerivs 2.0 Generic license

Tree with foil wrapped around injured part of tree, by James Pintar

Two photos within the Draper Natural History Museum by Curator, Corey Anco