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Welcome, woodpeckers: Nature's noisy little harbingers of spring

Posted March 21, 2010 11:00 pm

Valerie Blaine

It's springtime! And woodpeckers are drumming, drilling and banging to beat the band.

While spring is a welcome treat, not everyone is thrilled with the annual revival of woodpecker activity. These birds express their vernal exuberance on just about anything: dead trees, live trees, telephone poles, cedar shingles, aluminum siding, metal vents, downspouts and gutters.

This can be exasperating to people who prefer silent somnolence at dawn to percussive reveille. Can't these birds tell the difference between aluminum siding and a tree? In a word, no. Your house - especially if it's brown or gray - is just a big, weird tree to a woodpecker.

But first, some ornithological technicalities. Woodpeckers, in the family group known as picidae, both drum and drill. Drumming is percussion on a surface that resonates with vibration. Drilling is pounding a surface (usually wood) in order to chip away pieces of the substrate.

In the woodpecker world, percussion is part and parcel of courtship. The higher the male hormone levels in the springtime, the more urgent the drumming. Thus they persist on banging the daylights out of the aluminum, cedar, and metal "tree" (also known as your house) as well as real trees in the woods.

"Why don't woodpeckers just sing in courtship," you ask, "like birds are supposed to?" The best answer to that question is: because they can't. Woodpeckers are lousy vocalists. At best, they make sharp "Pic!" noises or "Qurrrrrr!" sounds. So serenading is definitely out of the question. Instead, they drum. And the girls dig their licks.

The more resonant the substrate, the better for love beats. The metal downspout on your house may be just the thing for a male woodpecker to express his love to an attentive female. Or, a male may impress females the old fashioned way, by drumming on a hollow old oak tree.

While all this noisy courtship is going on, woodpeckers also have to prepare nest sites. This is where the drilling comes in. Perhaps when you're on a trail - or in your yard - wood chips may fall on you. Look up, and there's likely a woodpecker chipping away to make a cavity in a tree (or your siding). Watch it for a while and see how industriously the bird works that tool - i.e., his bill - chiseling from right to left, left to right, a little chip here, a little chip there. He will drill diligently to make the cavity to his species' specifications.

When you see a woodpecker in action, note how it positions itself on the tree. There's a lot of physics involved. The woodpecker's head is just the right angle and distance from the tree to get the maximum force with each pounding. The angle of the body is achieved by virtue of two adaptations: specialized tail feathers and specialized feet. The tail feathers are very stiff. The tail thus props the body vertically on the tree. The sharply clawed feet are zygodactyl, meaning that two toes point forward and two point backward, securing the bird's grip. When the woodpecker is thus firmly mounted on the trunk of the tree, it can drum and drill with abandon.

Like banging your head against the wall, doesn't a woodpecker get a pounding headache? Here's where another adaptation comes in handy. There's a spongy cushion between the bill and the skull that absorbs the continual pounding. This flexible cartilage allows the entire head to be used as a jackhammer, with repetitive strikes of the bill - and no Excedrin headaches.

In addition to courtship and cavity making in spring, food is a big motivator to peck away at trees year-round. The Picidae are, for the most part, insectivores and they search under bark for tasty invertebrates. The tongue is supremely designed for invertebrate cuisine. It's extremely long - so long, in fact, that it has to wrap around the skull when retracted. When the woodpecker pokes a hole in bark, the elongated tongue uncurls. "It is extended by a complex system which includes very long tongue-base bones," explained Ehrlich, Dobkin and Wheye in "The Birder's Handbook."

"The tips of ... woodpecker tongues are barbed to help in extracting insects from holes, and the tongue is coated with sticky saliva, which helps to retain the prey."

Many woodpeckers appear to drill randomly in search of food - literally the hunt and peck method of finding what you want. Researchers have found that some woodpeckers locate their prey by listening. Downy woodpeckers, for example, can detect the munching, crawling and tunneling of insects underneath bark. This acoustical feat may determine feast or famine for these birds.

If your house is surrounded by trees, you may well have woodpecker neighbors. As long as they remain just neighbors and not uninvited guests banging on your siding, you can enjoy their presence. They will be helpful neighbors by consuming a prodigious quantity of insects.

While there's no guarantee that a woodpecker will refrain from drilling on your gutter, you can reduce the chances of this happening by creating and maintaining healthy habitat on your property. Healthy habitat for cavity nestering insectivores such as woodpeckers means a diversity of living trees and snags, or standing dead and dying trees. Tidying up by removing snags may make you feel good, but it results in habitat decline, and habitat decline leads to a paucity of picidae. So if you have a snag or two at the back of your property that won't harm anyone if they fall, leave them for the drill team.

Valerie Blaine is the Nature Programs Manager for the Kane County Forest Preserve District. You may reach her at blainevalerie@kaneforest.com.

A red-bellied woodpecker in a tree in a Naperville backyard. Ed Lee | Staff Photographer, 2004

Who's pecking on your tree?

Here are some local woodpeckers to look for.

Downy woodpecker: This small woodpecker is very common in wooded areas. It sports black and white feathers. Males have a red nape. They are busy and noisy throughout the year.

Hairy woodpecker: Essentially, a larger version of the downy. Its habitat requirements are more particular than the downy's. The hairy needs mature woods and is uncommon in our area.

Red-headed woodpecker: The striking bird has an all-red head and a black body with a large white patch. Arguably declining in number, the red-headed prefers open woodland habitat. The loss of habitat contributes to its population woes.

Red-bellied woodpecker: Often called a "red-headed" due to the bright red on the nape of both male and female, and the extended red on top of the male's head. The red-bellied has a faint, barely distinguishable red belly, but more importantly it has black and white bars on its back.

Northern flicker: This is a large bird with a serious bill. The flicker uses its bill to poke around on the ground for insects and other invertebrates. Its pattern and coloration make it very distinctive: a black breast-band, spotted belly, red crescent on the nape and, for males, a black line from the bill across the face.

Pileated woodpecker: The "Woody Woodpecker" bird, the pileated is big and striking in appearance. It sports a red crest, a long neck with white on the sides and black and white front and back, and an all-black back. These woodpeckers require large mature hardwood forests and are thus uncommon in Kane County. Carpenter ants are high on their list of delicacies.

Yellow-bellied sapsucker: This woodpecker only passes by during migration. Its yellow belly is most visible in flight. Otherwise, look for a red crown and indistinct white bars on its back. Yellow-bellies sapsuckers eat sap and the insects attracted to sap.

Woodpeckers and emerald ash borers

The infestation of the notorious emerald ash borers has been a boon to local woodpeckers, who relish the ash borer larvae in ash tree bark.

Unfortunately, the woodpeckers don't eat enough ash borers to make a dent in the pest population.

"Woodpeckers aren't a legitimate biological control," said Matt Williamson, plant ecologist with the Forest Preserve District of Kane County. Williamson explained that the magnitude of the beetle's reproduction is much greater than the hunger of local woodpecker populations.

And by the time the woodpeckers discover the tasty treats, the ash borer larvae have already created galleries, or tunnels, around the tree from top to bottom.

Researchers are looking for a different biological control of the emerald ash borer and are particularly interested in a species of wasp that parasitizes emerald ash borers in their native habitat in China.

It is being carefully studied for use here. Let's keep our fingers crossed that such a biological control will be successful.

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