A red-bellied woodpecker should not be at my feeder. Apparently he didn’t read the range maps. I’ve checked every field guide that I own and believe me, I own plenty. They all concur that Massachusetts is about as far north as red-bellied woodpeckers get. Yet, this fellow has been around my house all winter.

In truth, red-bellied woodpeckers have been stretching their territories into Maine for awhile. They were rare a couple of decades ago, but they are slowly becoming more common. They’ve also been expanding their range northwestward into the Great Lakes and Great Plains. While it is tempting to blame it on global warming, it’s more likely that the bird is just doing it on its own. They’ve had a long history of spreading out. Red-bellied woodpeckers are abundant in the southeastern United States, where every palm tree in the Everglades seems to have one. If you’re camping at the national park, it’ll be the bird you hear most often.

You’ll have to look closely in good light to see the pinkish wash across the belly that gives this woodpecker its name. Belly color is probably the least distinctive thing about this bird. A bright red patch across the back of the head and neck is much more noticeable. But since the name red-headed woodpecker was given to a different species, I guess whoever named this one had to get creative.

Woodpeckers are a marvel of engineering. You would be, too, if you spent your life banging your head against a tree. Its brain is well protected and cushioned inside its skull to avoid concussions. It has a transparent third eyelid for protection against flying wood chips and stiff feathers covering its nostrils. Special cells at the end of the bill regenerate the tip so that it doesn’t wear down with use. In fact, the chisel sharpens automatically with every blow.

Most woodpeckers have four toes. Unlike other birds, they have two in front and two facing backward to better grip the tree. However, a couple of our rare Maine woodpeckers lost a toe somewhere along the evolutionary process. The black-backed and American three-toed woodpeckers are the only North American land birds with three toes — two in front, one in back. They tend to chisel from the side on rough-barked trees that are easier to grip, so keeping a superfluous fourth toe warm in winter may be counterproductive. That’s only a guess, but since they are the two northernmost woodpecker species on the continent, I’ve got to think frostbite is part of the equation. Go ahead, prove me wrong.

Woodpeckers have stiff tails which they use to brace themselves for striking the tree. They have a long, sticky tongue with a barbed tip that can spear and draw insects out of the cavity. The tongue is two to three times longer than the bill and retracts into the skull in a way that provides additional padding for the brain when the bird hammers.

Even the color is adaptive. The black and white zebra striping on the backs of most woodpeckers is a disruptive pattern that breaks up the bird’s outline when it’s climbing up the tree. Every little bit of concealment helps.

Woodpeckers do not fatten up for the winter months. They spend the cold overnights sheltered in tree cavities, and snowfall never covers their food supply. At least nine species of North American woodpeckers also cache food for the winter, storing nuts and insects in bark crevasses. Out west, the acorn woodpecker actually drills holes in trees, utility poles, and fence posts for storing acorns. Known as granaries, these holes sometimes hoard thousands of acorns.

As a result, most woodpeckers are nonmigratory. In Maine, only yellow-bellied sapsuckers and northern flickers leave the state. The former relies on oozing sap to trap insects for some of its diet; the latter forages for insects on the ground, particularly ants. Neither is possible in winter. On the other hand, red-bellied woodpeckers can subsist on a diet of seeds in the winter and will readily visit a bird feeder. So this southern woodpecker seems to be doing just fine up here in the frozen north.

My woodpecker is definitely a male. Females retain the red patch on the nape of the neck but not on the cap. Plus, for a red-bellied woodpecker to wander this far astray, it would have to be a male. They never stop to ask for directions.

Bob Duchesne serves in the Maine Legislature, is president of the Penobscot Valley Chapter of Maine Audubon, created the Maine Birding Trail and is the author of the trail guidebook of the same name. He can be reached at duchesne@midmaine.com.