A long history of fire suppression in eastern U.S. deciduous forests has had an unintended effect, raising fire-intolerant species such as red maples to dominance at the expense of fire-tolerant oak trees. In an attempt to restore the oaks, researchers are experimenting with prescribed burning. But some biologists have worried that these burns might threaten ground-nesting birds in the area. If the results of a study appearing in the October Conservation Biology are any indication, their concerns are justified.

Vanessa Artman of Kenyon College and her colleagues studied the effects of prescribed burning on forest birds in four study sites in Ohio. Burning 50- to 75-acre areas with varying frequency, the researchers monitored 30 local bird species. After four years of repeated burning, they found that three ground-nesting bird speciesovenbirds, hooded warblers and worm-eating warblershad declined by more than 80 percent. According to the team, these declines resulted from burning-induced reductions in the leaf litter, shrubs and saplings that the birds rely on to build their nests.

On the other hand, two bird species increased as a result of the burns. American robins progressed from being rare to common and eastern wood-pewee populations almost doubled. Fires in these areas seemed to boost their foraging success. Nonetheless, the researchers conclude that long-term or large-scale prescribed burning could change the migrant songbirds that breed in eastern deciduous forestsperhaps for the worse.