If you hear a loud drumming coming from a tree in Connecticut, there is a good chance a woodpecker is nearby. These remarkable birds are familiar residents of our forests, backyards, parks, and suburban neighborhoods. Connecticut is home to seven species of woodpeckers, including the downy, hairy, pileated, northern flicker, yellow-bellied sapsucker, red-bellied, and red-headed woodpeckers.

Woodpeckers are much more than beautiful birds with impressive bills. They are keystone species — animals whose activities have an unusually large influence on the ecosystem around them. One of the most important things a woodpecker does is something we might not notice at all: it creates homes for other wildlife.

Woodpeckers are among the few birds capable of excavating their own nesting cavities in trees. Using their powerful bills, they chisel into wood to create a protected space for raising their young. Some species prefer dead or decaying trees, while others excavate cavities in living trees that have begun to deteriorate. And when the woodpecker moves on, its old cavity does not simply become an empty hole. It becomes real estate.

Chickadees, nuthatches, bluebirds, owls, wood ducks, squirrels, flying squirrels, and other animals can use abandoned woodpecker cavities for nesting or shelter. Many cannot excavate a cavity themselves and depend on naturally occurring holes — or those created by woodpeckers. Connecticut's Department of Energy and Environmental Protection identifies woodpeckers as important because their cavities provide nesting sites for birds and mammals throughout the state.

This is why woodpeckers are described as “ecosystem engineers.” Their work physically changes their environment and creates resources that benefit many other species. Research has also found that secondary cavity-nesting birds can have greater nesting success when using abandoned woodpecker cavities.

Connecticut’s pileated woodpecker demonstrates this better than any other. Our largest woodpecker, the pileated is roughly crow-sized and can be found year-round in many of Connecticut's larger forested areas. It particularly favors forests containing large, mature trees.

If you've ever found a tree covered with large rectangular holes or discovered a pile of fresh wood chips at its base, you may have found evidence of a pileated woodpecker. These birds excavate deeply into dead and decaying wood while searching for carpenter ants and other insects.

Their appetite for insects is another important part of their ecological role. Woodpeckers help regulate insect populations while turning insects hidden beneath bark and inside wood into food. Different woodpecker species specialize in different ways of finding that food, reducing competition among them.

The trees themselves are just as important. A standing dead tree, or snag, may look like something that should be removed from a forest or backyard. Ecologically, however, it can be one of the most valuable trees on the property. Snags provide food, nesting sites, perches, and shelter. Connecticut Audubon's forest-management guidance recommends retaining snags whenever it is safe to do so because they provide important habitat for woodpeckers and other wildlife.

This gives us an important perspective when we look at a dead tree. Instead of seeing only a tree that has reached the end of its life, we can see the beginning of another stage of its ecological life.

The tree becomes an insect habitat. The insects become food for woodpeckers.

The woodpecker creates cavities. And those cavities become homes for other animals.

That is the remarkable chain of relationships behind the seemingly simple act of a woodpecker drilling into a tree.

The next time you hear that unmistakable rat-a-tat-tat echoing through a Connecticut woodland, take a moment to look for nature’s carpenter at work. That woodpecker may be doing far more than finding its next meal.

It may be building the next generation of homes for an entire neighborhood of wildlife.

My Backyard Habitat is published monthly in cooperation with The Newtown Bee by Protect Our Pollinators. For more information or to reach out, visit propollinators.org.

Two juvenile pileated woodpeckers peer from their nest cavity. —Laura Mitchell photo

If you hear a loud drumming coming from a tree in Connecticut, there is a good chance a woodpecker is nearby.