Woodpeckers are unique birds that are known for hammering on trees with their sharp, chisel-like beaks. This rhythmic hammering produces a loud, rapid drumming sound that carries through the forest. But is this drumming or is it actually drilling into the tree? The answer lies in understanding the biology and behavior of woodpeckers.
What’s the purpose of woodpecker drumming?
Woodpeckers drum for a few key reasons:
- To establish their territory and attract a mate
- To communicate with other woodpeckers
- To excavate nesting and roosting cavities
- To find food such as insects and larvae hiding under bark
Drumming serves as a way for woodpeckers to loudly announce their presence and stake their claim on an area of the forest. The drumming calls can be heard for great distances and convey information to other woodpeckers about the territory. Drumming is often interspersed with vocal calls as well.
In terms of attracting a mate, the loud, fast drumming demonstrates that the woodpecker is strong and robust enough to hammer quickly and vigorously. This shows a potential mate that the woodpecker has good genes and would make a viable parent.
Anatomy of woodpecker drumming
Woodpeckers have several special anatomical adaptations that enable them to drum powerfully on trees:
- A straight, chisel-shaped bill made of strong keratin that can hammer on hard wood
- A long, barbed tongue that can wrap around bugs deep inside trees
- Strong neck muscles to withstand the forces of drumming
- Thick skull bones and a cushioning cartilage layer over the beak to absorb impacts
- Zygodactyl feet with two toes facing forward and two facing backward for gripping onto tree trunks
- Stiff tail feathers that provide additional support against the tree
These adaptations allow woodpeckers to hammer away at rates of 15-30 times per second, generating forces 1,200 times greater than gravity with no harm to their brain or organs.
How cavities are excavated
One of the primary purposes of woodpecker drumming is to excavate holes in trees in which to build their nests and take shelter. This process involves drilling into the wood – known as ‘excavating’ – which creates perfect circular holes.
Woodpeckers approach excavating a cavity methodically:
- They first hammer to locate any soft inner wood or insect infestations, like carpenter ants, which indicate good places to start excavating.
- They then switch to drilling, pecking repeatedly in the same spot to start a hole.
- The hole widens as they chip away the wood in concentric circles.
- They excavate deeper and deeper, periodically stopping to clear out the wood chips.
- The finished cavity is smooth-walled and nearly circular.
This excavating process can take weeks for a woodpecker to complete a single cavity. They need to drill through extremely hard outer wood on many tree species. Some species will excavate a new nesting cavity each year while others reuse old ones.
How they find food
In addition to excavating nesting and roosting cavities, woodpeckers also drill into trees to find food. Their drumming and drilling helps locate tree-dwelling insects like beetle larvae, ants, termites, and other arthropods hiding under the bark.
Woodpeckers can use their exceptional hearing to detect movement of bugs inside the trees. Their drumming and drilling helps both locate prey and soften wood to easier access food.
This foraging drilling is generally shallow as they probe just below the bark rather than making deep holes. The holes create sap flow that attracts more insects too.
Differences between drumming and drilling
Drumming and drilling serve different purposes for woodpeckers. There are a few key differences:
| Drumming | Drilling |
|---|---|
| Done for communication and signaling purposes | Done for excavating holes and searching for food |
| Involves rapid, shallow tapping that does not damage tree | Involves slower, repeated pecking in same spot to dig deeper into wood |
| Performed on resonant surfaces like dead trees or branches | Performed on live trees or softer, infested wood |
| Makes a fast, loud, drumming sound | Makes a slower, quieter drilling sound |
The key distinction is that drumming is communicate through sound and drilling is used to penetrate wood for functional cavity excavation or foraging.
Common drumming species
Many different woodpecker species engage in drumming behavior for communication and mating. Some widespread North American species that are known for their drumming include:
- Downy Woodpecker
- Hairy Woodpecker
- Northern Flicker
- Pileated Woodpecker
- Red-bellied Woodpecker
- Red-headed Woodpecker
These species all have specialized drumming muscles and beaks adapted for generating loud, rapid drumming sounds that convey their presence and fitness.
Downy Woodpecker
The Downy Woodpecker is the smallest woodpecker species in North America at only 6-7 inches in length. Despite its small size, the Downy Woodpecker can drum up to 28 times per second. Its drums are slower than larger woodpeckers.
Hairy Woodpecker
Very similar looking to the Downy, the Hairy Woodpecker is a bit larger at 9-11 inches long. Its drumming is louder and faster than the Downy, reaching up to 36 times per second.
Northern Flicker
The Northern Flicker is a less common species but very well known for its loud, ringing drumming that carries far through the forest. It excavates large nest cavities since it is one of our largest woodpecker species.
Pileated Woodpecker
As the largest woodpecker species in North America, the striking Pileated Woodpecker drums the loudest. Its hammering on dead trees produces a very loud, machine gun-like series of knocks that can go on for extended periods.
Red-bellied Woodpecker
While not quite as showy as the Pileated, the Red-bellied Woodpecker is another large, common species that drums frequently to establish its breeding territory each year. Its lower-pitched drumming is slower than smaller woodpecker species.
Red-headed Woodpecker
One of the most boldly patterned woodpeckers, the Red-headed Woodpecker is a strong excavator of nesting cavities and drummer to attract mates. It prefers drumming on utility poles and street signs.
Drumming sounds
If you hear woodpecker drumming sounds in the forest, how can you identify which species it may be? Here are some clues based on the sound:
- Very slow, spaced drums – Likely a larger woodpecker like Pileated or Northern Flicker
- Faster, steady drum roll – Probably a Downy or Hairy Woodpecker
- Slow double knocks – Could be a Red-bellied Woodpecker
- Fast and furious drums – May be a smaller Red-headed or a Downy
- Slow drums on a metal pole – Often indicates a Red-headed Woodpecker
The speed, spacing, pitch, and resonance of the drumming can give clues to which woodpecker species you are hearing even before you spot them visually.
Conclusion
In summary, woodpecker drumming serves as a form of loud communication to attract mates and establish territory while drilling is used for excavating cavities and accessing food. Their unique anatomy enables woodpeckers to drum powerfully without injury. While drumming produces sound but not wood damage, drilling penetrates the tree surface for functional use. Knowing the different drumming sounds can help identify the woodpecker species.
So whether you hear a rattling drum or see perfect holes appearing in trees, you can now appreciate the outstanding abilities of woodpeckers!
