Celebrating the Drum Roll
Essay by Stephen Shunk
The spring percussion of tiny jackhammers in the forest signals the beginning of breeding season for Utah’s woodpeckers. Each species’ signature drum roll is the woodpecker version of bird song, setting them apart from the rest of the world's avifauna. Except for one Australian parrot species, woodpeckers—and their close relatives, the piculets—are the only birds on Earth that communicate using an instrument. And this hammering doesn’t stop with communication. Many woodpeckers also feed by repeatedly slamming their heads against trees. And yet you don’t find woodpeckers with traumatic brain injuries at the bottom of their favorite trees.
Imagine slamming your head against a brick wall—which I don’t recommend—while traveling 16 miles per hour. This foolish act would subject you to a deceleration force of up to 1,200 g (1,200 times the force of gravity). For perspective, the highest documented impact a human has survived was 46.2 g. A severe car accident might subject your brain to 100 g of deceleration.
According to reliable medical sources, the 16-mph trick would cause massive diffuse axonal injury, instant fatal brainstem trauma, and severe coup-contrecoup injury. I’m not a doctor, but these things all sound very bad. Humans just haven't developed the structural adaptations to survive such an impact, but woodpeckers withstand these forces thousands of times a day as they go about their fascinating lives as forest carpenters. Communicating with an instrument sets woodpeckers apart from other birds. Surviving 1,200 g of deceleration makes them the gallant knights of the forest.
The anatomical adaptations that let woodpeckers survive their hammering make them one of the most specialized bird families. From top to bottom, their specialized skull structure, jaw hinges, neck muscles, vertebrae, upper ribs, and tailbone—among other parts—work together to distribute force away from the cranium. This anatomy story is pretty dang cool, but is that the end of it? Hardly. Woodpeckers are survivors, but they also play key roles in Utah’s forests, supporting a wide range of organisms, including birds, mammals, invertebrates, and more. These key roles make them keystone species.
Woodpeckers are housing developers. Each of the state’s nine breeding woodpeckers nests in cavities that they excavate themselves, a behavioral adaptation that works exceptionally well because of their specialized anatomy. In turn, 25 of Utah’s nesting bird species—not counting the woodpeckers—build their nests in woodpecker cavities. These species, including Wood Duck, Pygmy Owl, Tree Swallow, House Wren, and Lucy’s Warbler, depend upon woodpeckers to excavate their nest sites. Some of these secondary cavity nesters may use artificial nest boxes, but only because we have removed dead trees, or snags, from the landscape.
You can become a snag advocate. Work with land managers and encourage them to retain dead trees where they don’t jeopardize public safety. Reverse the paradigm that snags are ugly, and teach others that healthy forests comprise a broad range of age classes, including dead and dying trees. Support cavity conservation, and you'll support all of Utah’s cavity nesters. And next time you swear at a woodpecker for drumming on your house at 5 a.m., thank that woodpecker instead. That keystone bird supports a whole suite of cavity dwellers, and it makes your birding hobby a lot more fun.