Happy New Year to all.

Here in central New Hampshire we have three quite common woodpeckers that were all featured in last month’s blog about head banging. One of these woodpeckers, the Red-bellied Woodpecker, sports distinct plumage and a larger size than the other two. The Hairy and the Downy Woodpeckers on the other hand are almost identical twins and unless seen side-by-side can be difficult to distinguish. The Downy is our smallest woodpecker - much smaller than its Hairy cousin. The Downy is also less aggressive than its larger “twin.” The two are completely different species that diverged from a common ancestor around 6 million years ago - about as far back as when humans and chimpanzees went their separate ways. Curiously, however, they have grown to look more alike with time even though they are each genetically closer to other species. The Downy Woodpecker has grown increasingly to resemble the Hairy Woodpecker (not the other way around). Why would that be happening?

Why do small children want to dress up like superheros? To look powerful and capable of super feats, perhaps. For the demure, petit Downy looking like the big, bad Hairy affords some protection and maybe some advantages in the competition for food. Other birds may give way to a Hairy or to a Hairy look-alike at the suet feeder or along the trunk of a tree in the wild. This phenomenon, called mimicry, occurs throughout the natural world in which, for example, a butterfly might develop a resemblance to a toxic counterpart of a different species in order to avoid predators. Interestingly, there are a number of woodpeckers around the world that exhibit mimicry and have near twins in their habitats.

So how do you distinguish between these two birds? Well, the Hairy is bigger - about 9.5 inches long to the Downy’s 6.5 inches, and the Hairy has a longer, pointy-er beak - it’s about the length of the bird’s whole head while the Downy’s beak is more blunt and only the length of about half the head. Both birds have white outer tail feathers, but the Downy’s are likely to be streaked or spotted with black. Both have large white patches on their backs, but the white patches on the sides of the Downy’s neck are likely to be larger and more distinct. The Hairy Woodpecker is more likely to forage for food along the larger trunks of trees while the Downy Woodpecker will tend to forage along smaller branches. These similarities and differences are true for both males and females except that the males of both species have a red patch on the top and back of their heads.

Woodpeckers drum like other birds sing to attract mates and discourage competition. And like bird songs, their drumming is species specific. The larger Hairy has a much more rapid drumming with longer pauses (25 beats per sec), while the Downy is slower but with very short pauses (15 beats per sec).