For woodpeckers, the right tree can be hard to find

[Cara J]

Woodpeckers and other cavity-excavating birds worldwide are keystone species. These birds excavate their nests out of solid wood, and because their nests are often well protected against predators and the environment, other species use and compete for their old, vacant nests. The presence of cavity-excavating birds in forests has far-reaching effects on species richness and ecosystem health. Given the species’ importance, Teresa Lorenz, a research wildlife biologist with the U.S. Forest Service Pacific Northwest Research Station, wanted to find out why cavity-excavating birds do not use many trees seemingly suitable for nesting. This puzzle has eluded researchers for decades. Lorenz and her colleagues also wanted to know what role wood hardness plays in the birds’ nest site selection. The researchers found that across 818 snags in Yakima, Kittitas and Chelan Counties in Washington’s eastern Cascade Range, trees not used by birds had wood five times harder than trees that were. Such trees could not be used by birds simply because their wood was too hard for the birds to excavate. Within burns used by at-risk woodpeckers, 86 to 96 percent of seemingly suitable trees contained unsuitably hard wood. Wood hardness limits nest site availability for these declining species Researchers found [...]

 

Read more: http://wildlife.org/for-woodpeckers-the-right-tree-can-be-hard-to-find/