Biofuel and Birds

Willow plantations provide nesting habitat

Issues of energy independence, climate change, and pollution and habitat destruction associated with mining and coal-fired power plants are focusing increasing attention on alternate fuels. Wood produces a significant amount of energy in Great Britain and Sweden. The U.S. Department of Energy is now testing whether rapid-growth willows and poplars can produce biofuel in America.

If woody biomass proves economically sustainable, it could reduce the amount of coal burned at power plants. But what might be the effects on birds? In an article published in the March 2007 issue of Bird Study, a team led by André Dhondt, the Cornell Lab of Ornithology's director of Bird Population Studies, found that bird density and the number of species in willow plantation plots were comparable to those in typical shrublands and successional habitats, and significantly more than in soybean or corn fields. Dhondt's team found at least 21 species of birds nesting in study plots and at least 39 species using them regularly.

The willows are grown in even-aged, densely-planted stands that grow extremely fast. During the first year, a stand may reach more than seven feet in height, and by the end of three to seven years may be more than forty feet high. At this point, the entire stand is harvested to start a new cycle.

Cedar Waxwing by Roger Beebe

The four most frequent nesters in the study plots were the American Goldfinch, Cedar Waxwing, American Robin, and Gray Catbird. Red-winged Blackbird and Wood Thrush were also fairly common. Each species showed strong preferences for specific cultivars of trees. Dhondt said the birds preferred plants with strong branches radiating from a central stem, with numerous side branches forming a lattice-like structure. Birds avoided nesting in plants with long, whip-like stems susceptible to exaggerated movements in strong winds.

This research should help foresters select plants that provide continued habitat for birds even as agriculture for biofuel advances.

Dhondt said that staggered plantation schedules ensure that every year there are stands of each age. So this form of agriculture may help maintain breeding habitat for a range of open-habitat and woodland birds. Birds found nowhere near these stands may also benefit if we substitute biofuel for coal. Reducing mountaintop-removal coal mining will help Cerulean Warblers. And reducing the amount of mercury and other toxic emissions released into the atmosphere when coal is burned could benefit a great many birds.

—Laura Erickson

For permission to reprint all or part of this article, please contact Laura Erickson, editor, Cornell Lab of Ornithology, 159 Sapsucker Woods Rd., Ithaca, NY, 14850. Phone: (607) 254-1114. email: lle24@cornell.edu