Woodpeckers are amazing birds. I was shocked to learn that some people consider them pests! This is because of the harm that they can cause to living trees. Despite this harm, woodpeckers are crucial for the survival of so many species. Without them whole ecosystems would change. This is why scientists consider them to be a “keystone species.”
This post defines what a keystone species is and discusses how woodpeckers fill this role by providing food and shelter for other species. I also show how they’ve become important in the control of wood-boring insects that threaten many forest ecosystems.
In 1969, ecologist Robert Paine first used the term keystone species. He used it to discuss the role of the starfish
Today, the National Geographic Society describes a keystone species as, “an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether…This means that if the species were to disappear from the ecosystem, no other species would be able to fill its ecological niche.” In short, the loss of a keystone species would lead to the death of many others.
What makes the woodpecker a keystone species is its unique pecking behaviour. Woodpeckers peck cavities into trees to search for food like insects and sap and to create homes for themselves. Not only does this
Woodpeckers as Keystone Species
Woodpeckers are primary cavity excavators. This means they peck out homes for themselves in trees. According to Brydle, they quickly abandon these nests which become “used by many generations of secondary cavity-nesting species.” Different species of woodpeckers create different sized cavities which house different animals. Some animals that use these homes include owls, ducks, nuthatches, chickadees, squirrels, pine martens, bats, insects, voles, and raccoons. Often, these cavities are made in snags.
By pecking into trees, woodpeckers expose insects which they and other species feed on. What I find fascinating is the work of sapsucker woodpeckers. A study from Environment Canada describes how they “drill rows of small holes into deciduous and coniferous trees to feed on sap and insects attracted to these sap wells.” This food is important because it comes at a crucial time of year when many animals “are reproducing and storing fat for fall migration or hibernation.” Sap wells provide food for hornets, porcupines, hummingbirds, chipmunks, bats, squirrels, hares, wasps, bees, butterflies, and other animals.
Controlling Insect Populations and Damage
Woodpeckers have also played an important role in controlling invasive insect species. According to Natural Resources Canada, “studies have shown that birds, particularly woodpeckers, may feed on up to 75% of a population of wood borers and are probably the most effective natural control agent.” Many wood-boring species have threatened important forest ecosystems in Canada. In Ottawa and Halifax, scientists have credited sapsuckers with helping to control the emerald ash borer, a beetle which targets ash trees. They’re also important predators of the mountain pine beetle which has devastated forests in Alberta and British Columbia.
We shouldn’t be so quick to dismiss any species as a pest without understanding the role that it plays in any given ecosystem. The woodpecker might cause some damage to the trees in your backyard but they are essential to the overall health of our forests and its inhabitants.