Jul 17, 20203 min read

Cavity Visitors

Cavity-nesting species are an important component of many forest communities and there are a number of ways that these animals interact with, depend on, and compete for cavities. Woodpeckers, for example, are considered primary cavity excavators as they play a key role in creating holes in trees for nesting and roosting. Secondary cavity nesters can't excavate cavities themselves but take advantage of them once they are no longer being used, or sometimes even kick other species out (more on this soon!). Secondary cavity nesters will also use naturally occurring holes for nesting and roosting. A number of songbird species, ducks, birds of prey (think owls!), and small mammals fall into this group of cavity users. Finally, weak cavity excavators, often create their own cavities in decayed trees but will also use naturally occurring holes or cavities created by other species. Chickadees, downy woodpeckers, and nuthatches fall into this last category.

Red-headed woodpeckers are primary cavity excavators and if you've spent any time in the oak savannas at Cedar Creek you've probably seen them interacting with other species (most likely birds) near their nest or roost holes. They are fierce defenders of their cavities—sometimes even into the fall and winter months—and it's no wonder, given how much pressure there appears to be for use of these spaces. Cavities are a critical (and limiting) resource for many species and this creates a dynamic and constantly shifting landscape of cavity use and interdependencies among the species that use and depend on these spaces.

Observing these interactions over the last several years inspired some of us on the project to take a closer look at the goings-on at red-headed woodpecker nest and roost cavities. We wanted to learn more about how red-headed woodpeckers use and defend cavities and how other species fit into the picture. Our fundraising efforts allowed us to purchase a set of high-quality trail cameras, which we set up this spring. One of our most intrepid volunteers, Siah St. Clair, developed an attachment system to allow for an appropriate field of view without obstructing birds' access to the entrance hole and we're getting a lot of great images because of his hard work.

The cameras have captured thousands of photos and we are currently working on a way for volunteers to help us extract information from them on cavity use by red-headed woodpeckers and the myriad other species that makeup the animal and insect communities at Cedar Creek. The following images represent a small sampling of what the trail cameras have captured so far. Stay tuned for more details on that project!

White-breasted Nuthatch (left) and Great-crested Flycatcher (right) perched near an active red-headed woodpecker cavity at the Cedar Creek Ecosystem Science Reserve.

Downy Woodpecker (left) and Eastern Bluebird (right) perched near an active red-headed woodpecker cavity at the Cedar Creek Ecosystem Science Reserve.

Pileated Woodpecker (left) and Northern Flicker (right) perched near a red-headed woodpecker cavity that was previously used during the summer of 2019 at the

Cedar Creek Ecosystem Science Reserve.

A raccoon working very hard to get inside an active red-headed woodpecker cavity at the Cedar Creek Ecosystem Science Reserve. The lone woodpecker nestling survived this encounter and the raccoon moved on.