The Life of a Sapsucker

Last November26, I walked into our sunroom. Almost immediately I spotted a male yellow-bellied sapsucker eating the fruit of one of two hackberry trees we had planted more than a decade ago. Also called “sugarberry,” it is known to be a favorite winter food for a variety of songbirds, most notably American robins and yellow-bellied sapsuckers.

A portrait of a male yellow-bellied sapsucker

A portrait of a male yellow-bellied sapsucker (Photo by Claudine Lamothe on Flickr, Creative Commons license)

I had a bird’s eye view of this unusual woodpecker from our sunroom, which is perched on a hillock surrounded by black walnuts, black locusts, scarlet oaks, and a white pine. As I watched the sapsucker, he plucked and ate several hackberries and then flew down into the dead middle tree of the three large front yard black locusts and tapped away.

Next he flew to a black walnut tree branch outside the sunroom and probed in a crevice. Every time he withdrew his bill he had food in it that he swallowed so he was probably searching for and eating insects. Finally, he hitched his way past the crevice and began drilling small sap holes, but after a couple minutes he flew away.

As close as I had been to the sapsucker, I could not be certain what he was doing once he left the hackberry tree, but I could verify his attraction to hackberries. Since the weather had been mild, he was lingering later than the usual sapsucker migration period in Pennsylvania of late September through October. Or perhaps he planned to stay for the winter on our 1500-foot mountaintop as an occasional sapsucker has in the 47 years we’ve lived here.

A wintering yellow-bellied sapsucker alongside the Schuylkill River Trail, Chester County, PA

A wintering yellow-bellied sapsucker alongside the Schuylkill River Trail, Chester County, PA (Photo taken by Brian Henderson on Feb. 21, 2016, and posted on Flickr, Creative Commons license)

Male yellow-bellied sapsuckers don’t migrate as far south as the females, although most yellow-bellied sapsuckers migrate from their northern nesting grounds of southeast Alaska, the southern half of Canada, and our northern states where they breed as far south in the east as Pennsylvania’s northern tier. A few winter mostly in the southern part of the commonwealth, but the yellow-bellied sapsucker—the only woodpecker species in eastern North America that is completely migratory—usually spends its winter farther south in the United States, West Indies, Mexico or Central America.

As their name suggests, both the male and female yellow-bellied sapsuckers have dull, yellow bellies and breasts in addition to red crowns and black faces, wings, and backs accented by white patterning—two horizontal stripes on their faces, a broad patch on each wing, and stippling on their backs. But only the males have flaming red throats.

Because they sapsuck, they are nicknamed “sap-sippers” and “sup-saps,” and lap up leaking sap and any trapped insects with their specialized, brush-tipped tongues. Although they have drilled their sap wells in more than 1000 tree and woody plant species, they prefer sick or wounded paper and yellow birches, red and sugar maples and hickories, all of which have high sugar concentrations in their sap.

A yellow-bellied sapsucker on a tree with rows of holes

A yellow-bellied sapsucker on a tree with rows of holes (Photo by Vitalii Khustochka on Flickr, Creative Commons license)

In early spring they drill holes in xylem, the inner part of the trees, to obtain sap moving up the branches, but after trees leaf out, they drill shallow, rectangular wells in phloem, the part of the tree that carries sap down from the leaves. That sap may be 10% sugar and feeds not only sapsuckers but ruby-throated hummingbirds, which time their migration to that of sapsuckers to make use of this abundant resource. Tufted titmice, white-breasted nuthatches, black-capped chickadees, red-bellied and downy woodpeckers, and black-throated blue warblers have also sampled the flowing sap as well as bald-faced hornets, paper wasps, chipmunks, red squirrels, bats, porcupines, and martens.

While sap comprises about 20% of their yearly diet, they also eat a wide variety of insects, not only those trapped in the sap, but those they pry from under bark scales and catch in the air. Bast, the inner bark and cambium layers of trees, fruit, including berries of dogwood, black alder, Virginia creeper and wild black cherries, buds (in spring) and seeds complete their varied yearly diet.

Yellow-bellied sapsuckers begin returning to Pennsylvania by the third or fourth week in March. Here on our ridge-and-valley mountain, I first know they are back when I hear their peculiar mewing alarm calls sometime in early April. Then I find them quietly tapping and tippling in our woods. Usually they are males because they migrate a week ahead of the females. And here they seem to favor hickory trees which are already scarred with rows of old sapsucker holes. Hickory trees, it turns out, have a sap flow with a sugar concentration of between 6.4% and 11.1%.

A yellow-bellied sapsucker that returned to Pennsylvania

A yellow-bellied sapsucker that returned to Pennsylvania (Photo by Henry T. McLin in Codorus State Park, April 16, 2013 on Flickr, Creative Commons license)

One April day I watched two males flying at each other around a medium-sized hickory tree, fighting over possession of a favorite tippling tree. I settled down to watch as one quickly routed the other and started to “sap-sip.” He braced his tail against the tree at a 45 degree angle, gripped the bark with his feet, and dipped his beak into each hole two or three times. Each time he withdrew his bill it glistened with sap. Twice he had to stop and defend the tree from the other sapsucker before both birds flew off.

On another April day I watched a male sapsucker sipping sap from a huge old sugar maple tree above the Far Field Road. That tree had old and new sapsucker holes, and he drilled new ones as I watched, The flowing sap also fed flies but instead of eating them, he made a quick dive to the ground, plucked up an insect, and flew back to his original perch.

He occasionally glanced at me as I sat on the ground six feet away, but he continued his drilling and sipping. The latter he did by turning his head sideways and dipping his beak into each hole two or three times, being careful not to touch the sticky bark with any other part of his body except his feet and the tip of his tail.

Insects in the beak of a male yellow-bellied sapsucker

Insects in the beak of a male yellow-bellied sapsucker (Photo by ramendan on Flickr, Creative Commons license)

He also defecated a fine stream every three minutes by quickly lifting his tail away from the bark and squirting a good foot or so from the tree. In his Woodpeckers of Eastern North America, Lawrence Kilham wrote of watching a sapsucker drilling in a black walnut tree during a January thaw in Washington, D.C. He noted that in a 25 minute period, one sapsucker voided 11 times or once every two minutes.

I didn’t hear the distinctive irregular drumming of a sapsucker. Mostly they drum on their breeding grounds to defend their territory and especially their sapsucking sites. Here in Pennsylvania they breed in the forests of our northern tier with 44% of our state’s estimated 96,000 birds in Warren, McKean, Potter and Tioga counties alone.

According to biologist Bernd Heinrich in his One Wild Bird at a Time, “the male drumming attracts the female, and that when she arrives he leads her to his previously found nest site [in a tree with hardwood decay fungus]. If she approves, she lets him know by offering token help, and then he begins excavating in earnest.”

A male yellow-bellied sapsucker checking out a potential nest hole

A male yellow-bellied sapsucker checking out a potential nest hole (Photo by Keith Williams on Flickr, Creative Commons license)

Sapsuckers are monogamous during their breeding time and often from year to year because they frequently return to the same breeding site, tree, and even cavity as the previous year. While he takes two to three weeks to drill a new nest cavity, she spends her time preening and resting. The entrance hole is a tight 1.5 inches and the nest cavity as deep as 10 inches.

She lays five to seven white eggs on a bed of wood chips left over from cavity construction and both parents incubate them with the male taking on some of the day hours in addition to the night shift. After 10 to 13 days, the naked hatchings emerge. The parents take turns brooding their young and feeding them insects often coated in sap.

Most nests are 9.8 to 45.9 feet from the ground and the nestlings are noisy which may attract predators. Kilham reported weasel predation in nests he observed in New Hampshire. Other predators include raccoons, snakes, red squirrels, hawks and black bears.

An immature yellow-bellied sapsucker

An immature yellow-bellied sapsucker (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

At 25 to 30 days old, the young fledge but continue with their parents who feed them for a week and teach them sapsucking. The fledglings quickly learn to capture insects in the sap wells, but even after they feed themselves, they keep in vocal contact with their parents and use their sap wells. About six weeks out of the nest, they can drill their own sap wells but appear to stay in family groups at least until migration.

Yellow-bellied sapsuckers have been increasing throughout their range according to the 2011 Breeding Bird Survey. In Pennsylvania between the first and second breeding bird atlasing, breeding increased 99 percent Scott H. Stoleson reported in the Second Atlas of Breeding Birds in Pennsylvania. Although sapsuckers did not increase in the Allegheny Mountains where they once bred, they filled in and expanded in the northern, eastern, and western sections of Pennsylvania. Thus we can rejoice that such a unique woodpecker thrives in the commonwealth.

April Journal Highlights (2)

Close encounters of the avian kind

April 18. The sun warmed the Far Field, and as I walked Pennyroyal Trail, a towhee sang, a flicker called, and a ruby-crowned kinglet sang. I stopped to “pish,” hoping to entice the kinglet into view, and I did. He flew on to a tree branch, erected his ruby-crown, and sang, giving me my first look at what I had been hearing for weeks.

I went on to the woods beyond the Far Field where a brown-headed cowbird sang and a ruffed grouse crept off into the underbrush. I imagine he was the drummer I stalked back in early April. Sitting still on a moss-covered, old log, I also heard a red-bellied woodpecker, eastern towhee, and northern flicker as the dead leaves rustled in the wind.

The sun quickly disappeared, and I picked my way through the woods until I encountered two excited white-breasted nuthatches on a tree trunk. At first I thought they were courting, but then I realized that they were drinking from sap wells. They were quickly driven off by a male yellow-bellied sapsucker.

As soon as he disappeared higher in the tree, the female nuthatch returned for a few furtive sips. Still, the sapsucker quietly worked on new wells, sipped from old ones, and chased off a ruby-crowned kinglet. Occasionally the male sapsucker flicked his wings as he worked or flew over to an adjacent grapevine as if to rest. Surely there is no tasty sap in a grapevine. The irrestible sap wells are on a pignut hickory, as usual, and it is encircled up its trunk with old sap wells.

The nuthatches returned, calling softly, as they drank from the lower sap wells while the sapsucker worked high in the tree drilling new ones. At last I left the relatively peaceful scene, two species sharing one resource.

April 20. I used my turkey call as I sat in the spruce grove and called in a hen turkey. She came close to my hiding place at the edge of the grove and then retreated back to the edge of the woods along First Field Trail, clucking all the way. I’ve never called in a hen before, but according to one of our turkey hunters, that’s not unusual. Still, experts disagree on why they respond to a hen call. Is she already setting on eggs and defending her territory? Is she a scout for a male turkey or trying to keep rivals from joining “her” gobbler? Is she recruiting more hens for “her” gobbler? Is she merely curious? Are there reasons that we can’t even imagine?

Then, walking back on the Far Field Road, I scared up a gobbler. He, of course, saw me and ran, but I did get a quick look at his long beard. Was he still searching for hens? If only I had tried the hen call along the road. Oh well! It’s obvious that the turkeys are restless and have perhaps not gotten together yet due to the cold.

Above the barn on Butterfly Loop at dusk, the woodcock called, turning around to direct his call in all directions as we watched from a respectable distance.


Gray squirrels and masked shrews: social behavior

April 21. At least three young gray squirrels were born in the black walnut tree nest hole beside the driveway. Today they emerged for the first time, or at least two of the three did. I sat watching on the veranda as first one emerged and stayed out, exploring nearby branches. Then the second emerged more briefly and stayed closer to the nest hole before going back into it again. Each squirrel chewed about the hole entrance, hanging upside down before emerging. When both squirrels were out, a third one peered timidly out of the hole, but stayed inside. All their climbing about, peering in and out of the hole, even their chewing was silent. But scolding from a distant adult squirrel sent them all back into the den hole with one looking out. Three adults harvested black walnuts on the lower lawn.

The first six-spotted tiger beetle gleamed bright green on the driveway.

April 23. The gray squirrel family, even the shy one, played in, out, and around their nest hole as we watched from the veranda.

April 24. I heard a black-throated green warbler in the woods near the powerline right-of-way singing both his songs. As I stood listening and watching, a masked shrew dashed in and out of the leaf duff along an old, barkless, fallen tree. I sat quietly, watching for the shrews, and heard the first blue-gray gnatcatcher of the season. As I continued on the trail, a pair of mallards flew past on the powerline right-of-way, heading toward the First Field. Were they the same mallards Dave saw earlier in the morning? Had they gone back to Sinking Valley? Who knows? But at least I saw them.

More masked shrews chased in the woods on the other side of the powerline right-of-way. They crossed right in front of me for several minutes so I sat down on the trail and watched as they dashed back and forth across the trail, always using the same pathway at my feet. They were tiny, grayish-brown, with peculiarly-shaped snouts that identified them as masked shrews. I counted half a dozen or more chasing about. They were silent to my ears except for the rustling in the leaves. The books say that they are looking for food, but I only see this phenomenon in April and sometimes in July and I think it has to do with mate-chasing. None of the books say anything about their sex life. I suspect they have two broods a year, but I can’t prove it. Finally they stopped and I continued my walk.

The return of the wood thrush

April 27. Sitting on the veranda reading near dusk, we heard the first whip-poor-will of the season singing above the garage at dusk.

April 28. A pair of northern flickers checked out the black walnut tree squirrel den. Were they waiting until the young gray squirrels leave so they could take over the nest hole?

April 29. I stepped outside early to listen for the wood thrush, but the towhees were so loud they blocked out more distant sounds. Still, I did hear a faint portion of a wood thrush song. I stopped and gave thanks that another spring had come and with it wood thrush music–three months of heavenly singing before they once again leave us.

On Dogwood Knoll a rose-breasted grosbeak sang. And then, as I descended the knoll on a path of blooming dwarf cinquefoil, I heard the singing of a Louisiana waterthrush above the dark place. Halleleujah! We have at least one singing male. I sat on Turkey Bench to listen to his ringing tones.

Down near the bottom of the mountain I heard the “tick-tick” scolding tones of another Louisiana waterthrush. I rested on a moss-covered log beside the stream, still hearing but not seeing the waterthrush.

Bruce came down the road and a small, black, white and orange moth spun around his hat and landed briefly on it. Then it landed on my hat and Bruce photographed it. It was a grapevine epimenis, Psychomorpha epimenis — an early, day-flying moth whose caterpillar feeds on grapes. Truly a beautiful little creature.

In mid-afternoon, Steve pointed out a black vulture sailing over First Field.

April 30. At breakfast I watched a northern flicker throwing to the wind the remains of the squirrel nest in the walnut tree. Those flickers had been checking on the den every day, evidently waiting until the squirrel family dispersed.

Walking up Guesthouse Trail, I finally heard the wood thrush singing clearly. Wild black cherry and striped maple trees have leaved out and already my view into the woods has diminished.
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See also my post at the Plummer’s Hollow blog, Spring wildflowers: back on track.