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Protecting Songbird Habitats

by Kim Carlyle


It's not just the loss of trees that threatens some songbirds.

What’s beneath those trees — the water and wetlands that support the birds’ habitat — is as important to some bird species as the trees themselves.

A study of songbirds that live in floodplain forests in Arkansas may help foster good forest and river management decisions.

“Results of our study already have been used to modify forest management plans on the refuge,” said Robert J. Cooper, a University of Georgia wildlife ecology professor. “I only hope they will be taken into account when these water management projects are reviewed as well.”

Cooper and graduate student Jill Gannon investigated the effects of various timber-harvesting methods on the reproductive ecology of prothonotary warblers living in the White River National Wildlife Refuge. Their findings were presented at the Ecological Society of America’s annual meeting last August.

The 148,000+ acre refuge, mostly bottomland hardwood forest, floods regularly in winter and spring and is managed for habitat diversity, among other objectives. “Most songbird species in this kind of forest are neotropical migrants. As a group, those birds are declining,” Cooper said. The researchers chose the prothonotary warbler as a research focus because of its relationship to this kind of forest.

“Virtually every ecosystem has at least one bird species that is so intimately tied to that system that the species could be seen as an ecological indicator,” Cooper said. “The prothonotary warbler is found virtually nowhere other than forested wetlands, and that is the primary makeup of this area. That is also why it is so important to assess the effects of our land management decisions before they are implemented.”

The study was designed to assess the effect of timber harvesting on nesting birds, but water levels had a far greater effect on the warblers’ success, leading Cooper and Gannon to conclude that three proposed water management projects on the White River — which would alter flows in the river and its floodplain — are a significant threat to the ecosystem.

The major cause of nest failure was nest depredation by raccoons, woodpeckers and other predators. Years with normal flooding resulted in higher nest success.

“In dry periods, nests are relatively unprotected and alternative aquatic prey are not as readily available to predators,” Cooper said. “If we listen to what this indicator is telling us, then the threat to the river basin from the water management projects is real.”

Timber harvesting in the study was designed to mimic nature. Using both single tree selection and small patch cuts — clear cuts of no more than five acres — the scientists found that while treated plots temporarily had fewer birds on them, productivity of remaining pairs seemed unaffected.

“Barring other ecological changes, we expect densities of forest bird [populations] to recover as the forest grows back,” Cooper said.

For more information, contact Robert Cooper at


Research Communications, Office of the VP for Research, UGA
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