Woodpeckers Learn about the amazing birds in the family Picidae. Their special adaptations make them excellent at excavating wood. Several outstanding features make woodpeckers so easy to tell apart from other birds. Let’s quickly go over these features now and then I’ll get into more detail on some of them later. The first feature is the fact
, well, woodpeckers peck wood. The name says it all. In Spanish, a woodpecker is called a pájaro carpintero—a carpenter bird. I imagine that in most languages the name for these birds captures the wood-destroying aspect of their behavior. Woodpeckers have a straight, chisel-shaped bill. This is a finely-honed tool for excavating wood. What they’re looking for beneath the surface are insects to eat. A long, thin tongue helps them snatch bugs out of little crevices and tunnels they expose in rotting wood. The posture and movements of woodpeckers are distinct. They tend to hitch themselves up tree trunks while in an upright posture. These movements often look herky-jerky. And when woodpeckers fly, many of them have a bounding or undulating flight path, where they rise a little as they flap their wings and fall a little between bursts of flapping. Stiff tail feathers and strong feet allow a woodpecker to brace itself against a tree while whacking at the wood. Besides digging for insects to eat, woodpeckers also use their bills for communication and for excavating their nests. They communicate with each other by drumming against wood to make a loud sound. Drumming is one of their unique features. And all woodpeckers are cavity nesters. Most of them create their nests by chipping out a deep hole in wood. Many woodpecker species have bold black-and-white coloration, on just the head or over most of the body. Splashes of red and yellow are common. And quite a few species have greenish wings. Despite these general patterns, there’s plenty of color variation across this diverse bird family. There’s no one pattern seen in all woodpeckers. Evolution Millions of years ago, the ancestor of all woodpeckers figured out how to access a rich and mostly untapped resource: juicy and nutritious bugs burrowing around in wood. Natural selection favored individual birds that were better at digging into wood and capturing prey. And so the woodpecker was born and the world has never been the same. Today, there’s a boatload of woodpecker species. They’ve been successful in their unique lifestyle, their niche. They have adaptations that make them really good at what they do. Most of the salient features of woodpeckers that we just talked about relate to their special adaptations. But these traits didn’t appear all at once in prehistoric woodpeckers. It took a long time. A study published in 2012 offers a model for the stepwise evolution of traits that allowed woodpeckers to become more and more specialized. By analyzing anatomical and behavioral data from across most of the modern woodpecker lineages, the researchers in that study came up with this progression: The earliest woodpeckers could drill into wood to find bugs, but they didn’t have strong enough skulls to excavate their own nests. And they couldn’t climb up tree trunks. In the next step, they developed reinforced, tougher skulls and bills. That allowed them to hollow out their nests. In the last steps, their toes moved into their modern arrangement and their tail feathers got stiffer. With strong, grippy feet and a rigid tail, they developed a support structure that allows for tree trunk climbing shenanigans. Now let’s rewind to those very first, ancestral woodpeckers. Where did they live? The actual geographic origin of woodpeckers is still a mystery. Scientists have been using fossils, comparative anatomy, geographic distribution, and DNA sequences to figure out where and when woodpeckers first hopped onto the scene. The reason we can’t say for sure where these birds originated is because different lines of evidence support wildly different scenarios. For example, if you look at the high species diversity of the relatively primitive piculets in South America, that would suggest that the woodpecker family got its start on that continent. But there are a few older but less diverse lineages in the Old World. And that’s also where the oldest woodpecker fossils have been found. The most likely origin story for woodpeckers is that they first evolved in the tropics of Eurasia, about 45 million years ago. Around that time, the ancestor of all woodpeckers became a distinct creature, splitti
ng off from the lineage that became the modern honeyguides. Honeyguides live in Africa and Southeast Asia. They’re the closest living relatives of woodpeckers. The oldest woodpecker fossil we’ve discovered is a leg bone from Germany. It’s from a bird that lived about 25 million years ago, during the late Oligocene Epoch. So this is one of those fossils that supports the Eurasian origin of woodpeckers. The earliest evidence of woodpeckers from the Western Hemisphere is a feather suspended in amber from the Dominican Republic in the Caribbean. That fossil is from about 23 million years ago. Woodpecker evolution and species diversification really got cooking starting around 14 million years ago. They spread around the world and evolved into hundreds of species. They came into their own, occupying their specialized niche as arboreal, forest-dwelling, tree-drilling, bug-eating machines.