by John Shackford
The Hairy Woodpecker (Picoides villosus) is told from the Downy Woodpecker (Picoides pubescens) by having a longer, heavier bill, and an extra two inches or so of overall length. Also, there is a subtle difference on the white outer tail feathers of the two species: the Hairy has no black bars, while the Downy does, a distinction that can often be difficult to determine. These two are the only North American woodpeckers that have white down the middle of the back. If your ears are musically inclined, you probably won’t have much trouble telling the high-pitched “squeak-toy” note of the Hairy from the lower-pitched note of the Downy. But this difference can be somewhat difficult to sort out for less sensitive ears, especially if a call is not heard well or one is not that familiar with the notes of both species. And opportunities to hear this bird in this part of the country are not all that frequent: even though 57 birders participating on our Christmas Bird Count, we found no Hairy Woodpeckers.
Bent (A.C., 1964, Life Histories of North American Woodpeckers) has some interesting comments about the Hairy Woodpecker. As to how these woodpeckers locate tree-boring larvae, Bent quotes Dr. Thomas S. Roberts who says that “[a]ll the special senses of birds are very highly developed and it seems probable that in this case [Hairy Woodpecker] hearing, touch, and smell all may play a part. The active grub, as it crunches the wood, makes a sound that would surely be audible to a bird with its keen sense of hearing. The tunnel produces a cavity which would give both a different sound and feeling on tapping over it. Such things as grubs have a strong odor, and it is probable that this plays a part also.”
Bent also relates an interesting story V. A. Alderson published in the “Oologist” in an 1890 article entitled “Hairy Woodpecker and potato bugs” (I believe these are the same as the Colorado potato beetles, adults of which are 2/5ths of an inch long, and 1890 was definitely before wholesale modern-day sprayings). Alderson talks of an infestation of “potato bugs [that] covered every patch of potatoes…” in Marithon County (his home county), Wisconsin, except for the field of one farmer. This farmer took pains to find out why he didn’t have an infestation, and he observed a Hairy Woodpecker “making frequent visits to the potato field and going from there to a large pine stub a little distance away.” After about six weeks, the farmer visited the pine stub, saw a large hole about fifteen feet up, cut down the stub, split it open, and found “over two bushels of bugs. All had their heads off and bodies intact.”
Early ornithological literature (before field guides) would sometimes say that such-and-such a bird ate a lot of harmful insects and not very many that were beneficial. At times—it seemed to me—this was a somewhat strained defense of a particular species, but this was back in the day when birds were not protected by law, and such “kind” words about a species probably did change the behavior of some hunters. Now—I think we would all agree—the beauty and novelty of birds are reasons enough to protect them, but to learn of a Hairy Woodpecker that gathered two bushels of potato bugs in six weeks is impressive. The same general principle, eating lots of bugs, no doubt extends to many other bird species as well. So maybe over a nesting season, a Purple Martin colony really does eat a gazillion mosquitoes!