Beloved lookalikes: The downy and hairy woodpeckers
There are two beloved and familiar Minnesota woodpeckers that most everyone knows about and enjoys observing. And though each species looks remarkably similar, the two are distinct in both subtle and obvious ways. You might've guessed already which species I'm writing about. Indeed, they're the hairy woodpecker and its look-alike diminutive cousin, the downy woodpecker.
Both species of woodpecker have nearly identical ranges across North America. Occurring in almost every conceivable woodland habitat from Alaska, Canada, and throughout the lower forty-eight, it's curious that the two species evolved together and that one didn't end up being outcompeted by the other. One would assume that the larger, hairy woodpecker would dominate its smaller relative the downy, but that of course is not the case, and never apparently was.
The hairy woodpecker is a robin-sized bird that's two inches or so longer than the sparrow-sized downy woodpecker. If not observed side-by-side, it might be difficult to readily identify one or the other species definitively, but there are a few diagnostic traits that astute birders key in on.
Size is the obvious trait, but size isn't always evident. Each of the birds' bills, however, are different, and noticeably so, if you know what to look for. One of the ways I like to explain the difference is this way: if the bill of the woodpecker is about as long as its head is, then you're looking at a hairy woodpecker. But if the bill is only about half as long as its head is, then the bird is most assuredly a downy woodpecker. Large thick bill equals the large hairy woodpecker, and small thin bill equals the small downy woodpecker. Easy, right?
One other distinguishing physical feature between the two species is the "comma" mark. On the hairy woodpecker there is a well-developed "comma-shaped" black mark that extends from the shoulder onto the breast of the bird. This feature is far less obvious on the downy woodpecker, and in some cases, absent altogether. The next time you see a hairy woodpecker, look for this feature, or compare the two species by examining photos of the birds in your favorite guidebook or Internet website.
Another distinction between the two lookalikes is not something you see but rather something you hear—their vocalizations. Whereas the hairy woodpecker's call is a loud "peek", the downy woodpecker's call is a much softer delivered "pik." Additionally, hairy woodpeckers are well known for emitting a telltale rattle call, which is very similar to the belted kingfisher's rattle vocalization.
But what about the names of these species of woodpeckers? Why is one "hairy" and the other "downy"? Good question, right? While yours truly cannot make the leap that a feathered bird looks "hairy", the name is derived from the fact that hairy woodpeckers have what are called "filoplume" feathers, which are thin feathers located on the legs, head, and upper mandible, thus giving hairy woodpeckers an overall "hairy" appearance.
On the other hand, downy woodpeckers are so-named because of the soft texture of their back feathers, or "downy" appearance. In fact, many a birder affectionately refer to downy woodpeckers as simply, "downies." Even so, there are other birders that argue the name "downy" comes from the high-pitched notes that descend in pitch toward the end of their calls, thus their name "downy," it is reasoned, refers to the downward spiral of their calls, not the supposed texture of their back feathers.
The calls of hairy woodpeckers do not descend in pitch, which is another notable, albeit auditory, difference between the two species.
So there you have it. The most common and widely distributed species of woodpeckers in North America — the downy woodpecker and the hairy woodpecker — lookalikes they are, yet each with their own unique differences for us to see, hear, and appreciate as we get out and enjoy the great outdoors.