Study: Mega-fires may be too extreme for fire-dependent woodpeckers

Researchers in Black-backed Woodpecker habitat — a burned forest. Photo by Jean Hall

Fire is a natural part of western forests, but the changing nature of fire in many parts of North America may pose challenges for the Black-backed Woodpecker, a species that specializes in using recently burned forests but is picky about exactly where it settles. New research published in The Condor: Ornithological Applications suggests that the woodpecker prefers to nest near the edges of burned patches ⁠— and these edges are getting harder to find as wildfires have become bigger and more severe.

Black-backed Woodpecker
A Black-backed Woodpecker tends to a chick in a nest. Photo by Jean Hall

Andrew Stillman, a Ph.D. candidate at the University of Connecticut, along with colleagues from the Institute for Bird Populations and the U.S. Forest Service, looked at nest site selection and nest success of Black-backed Woodpeckers in burned forests of northern California. Over a period of eight years, the researchers located and monitored more than 110 nests while measuring nest site characteristics across multiple spatial scales. The birds in the study strongly preferred to nest in severely burned stands that had lots of dead trees. But the birds chose to place their nests near the edges of these high-severity burned patches, typically within 500 meters of a patch with live trees.

“We didn’t expect to find these woodpeckers nesting so close to edges,” says Stillman. Previous studies had shown that woodpecker nests closer to living forest patches were more likely to be preyed upon by animals such as squirrels. However, another recent study by Stillman and others showed that Black-backed Woodpecker fledglings often move into living patches with good cover quickly after leaving their nest. By placing nests closer to edges, adults may be providing their offspring easier access to this “nursery” habitat.

Stillman notes that “pyrodiversity,” or a diversity in age, size and severity of burned patches, appears to be important for this post-fire specialist woodpecker because it provides more edges between different burn severities. But climate change is fostering larger, more homogeneous fires with reduced pyrodiversity.

“The thing about pyrodiversity is that we expect it to decrease,” says Morgan Tingley of the University of Connecticut and co-author of the paper. “Every year we see more mega-fires, and these fires are quite homogenous in their structure, leading to low pyrodiversity. So even though the future is expected to hold more fire in western forests, the outlook may not even be good for fire-loving species.”

Stillman anticipates that understanding the importance of habitat edges to Black-backed Woodpeckers, as well as other findings of this study, will assist forest managers. “We hope that these results provide some of the missing information necessary to balance post-fire logging activities with the habitat needs of woodpeckers,” he says.

Rodney Siegel, executive director of the Institute for Bird Populations and a co-author of the study, agrees. “A central goal of our multi-year partnership with the Forest Service is to better understand the specific habitat needs of Black-backed Woodpeckers and other species that use burned forests. This information allows forest managers to design management activities that are more compatible with the needs of wildlife.”

Thanks to the Institute for Bird Populations for providing this news.

 

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