The Littlest Woodpecker of All
by John Trott, Contributing Columnist

Soon after sunrise on a morning in late September I heard a tentative, rhythmic tapping outside my study window. I couldn’t locate the bird but knew it to be a downy woodpecker from the exploratory, almost questioning, sound of the tapping. Was it one of the pair that nested in the big Norway maple in the side yard?

I never found the nest. It was probably in some partially decayed branch high in the tree. These little black and white woodpeckers are a major presence in the yard; tapping, calling the familiar pick note and, on occasion, singing the whinnying "song" that descends in pitch. Being non-migratory, the downy woodpecker is always here, a bird I can count on at any time of the year.

Both male and female are frequent visitors to the feeder for suet, Lee Trott’s bird pudding, and sunflower seed that the bird takes to the maple tree, wedges into a crevice, and whacks away to get the kernel.

In these mild, late-summer days, Lee Trott and I are enjoying meals at the round table in our side yard. Yesterday we watched a female downy woodpecker at the suet feeder just a few yards away. She is quite tame and seems unaware of our presence. I say female, though it may be a young male. The bright red spot on the back of the head of the male does not appear until after his autumnal molt, when he replaces his feathers with bright new ones.

Like all woodpeckers, the downy lives in a vertical world as he clings to the trunk of the maple tree with zygodactyl feet: two toes in front and two behind. Other birds in the yard — chickadees, titmice, cardinals and robins — have a three-in-front and one-behind toe arrangement. This is effective in perching across a twig and walking or hopping on the ground.

Woodpeckers also have stiff tail feathers that they use in propping on a tree trunk when excavating for insects within the tree. They can hear beetle larvae moving around so know exactly where to dig. A thick but spongy skull absorbs the shock of forceful wood-digging.

Piocoides pubescens is the scientific name of the downy. At just under six inches long, it is the smallest woodpecker in North America. Its name is derived from both Latin — picus meaning simply "woodpecker" — and Greek — eioides translating into "resembling." The downy does not resemble a woodpecker, it is a woodpecker! There is some scientific confusion there. Pubescens refers to the soft feathers at the base of the downy’s short bill. Ornithologists speculate that these feathers protect the bird’s eyes when chips are flying.

The 71/2-inch hairy woodpecker, Piocoides villosus, is almost identical to the downy except for a distinct difference in size. The bill of the downy woodpecker is much shorter in proportion to its body than the long, typical woodpecker-like bill of the hairy. This identical-except-in-size occurs in other birds: sharp-shinned and Cooper’s hawks and in sandpipers, greater and lesser yellowlegs. Evolution has worked a curious magic in these species, for a survival purpose not yet understood.

When working over a tree trunk, a downy will dodge or slip around if a predator appears. If the predator is a hawk, the big bird is momentarily confused when searching on the other side of the tree for what he hopes will be a future meal. His prey has disappeared! The downy has flattened itself against the tree trunk and looks like part of the bark. The bird is motionless and depends on this and protective coloration to escape detection. The downy will also slip around the tree when human watchers move in too close.

It is possible that the tapping I heard this morning was a downy woodpecker excavating a sleeping chamber for the winter. Though a pair of downy woodpeckers remains mated throughout the year, each excavates separate sleeping cavities for the fall and winter.

In March the pair will begin serious work on a nesting cavity with an entrance of 11/4 inches in diameter. At the bottom of this gourd-shaped excavation, a bowl is hollowed out in which white eggs are laid. No nest material is required; soft wood chips do very well instead.

Since a pair of downy woodpeckers uses a nest cavity for only one breeding season, last year’s nesting hollow will be available for other birds that do not build open nests. Chickadees, titmice, bluebirds, nuthatches and house wrens seek out and build their nests in last year’s downy woodpecker nest cavity. It’s a sort of recycling that benefits a number of birds and even small mammals such as flying squirrels.