Woodpeckers, Cavities, and Snags: Changing a Stubborn Paradigm

Most woodpeckers excavate their own nest and roost cavities, and most do so each breeding season. Where woodpeckers live, the abundance of cavities increases each year, and, more than 40 other North American bird species—not including the woodpeckers themselves—exploit this abundance for their own nests.

Cavity excavation is their “signature behavior” elevating the woodpeckers’ ecological significance in disproportion to their relative abundance, the very definition of a “keystone” organism. Remove the keystone from a stone arch and the arch collapses; remove woodpeckers from the forests, and cavity-dwelling wildlife communities face collapse.

Certain necessary conditions, known as “limiting factors,” must exist for woodpeckers to perform this keystone role. One such factor is the availability of nesting sites—in this case, the availability of dead trees, or snags.

Sadly, our general perception of snags—our current snag paradigm—labels dead trees as ugly and unsafe. And, snags have no place in a live forest cultivated solely for its timber.  From urban parks to suburban neighborhoods, and from rural woodlands to remote forests, we are inclined to remove snags from the landscape.

A healthy woodland comprises trees of diverse size and age, including dead trees at varying degrees of decay.  We can help woodpeckers perform their keystone roles in wooded ecosystems by changing the way we think about snags.

To learn more about how you can support cavity-dwelling wildlife, visit www.cavityconservation.com, and come see Steve Shunk’s presentation on September 21st.


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