Bird species in US plummet as habitat dwindles

Hundreds of species of birds, including many once-common songbirds such as the meadowlark and bobwhite, are in severe decline in the United States, falling in population by as much as 90 percent since the 1960s, scientists, government officials and conservation groups told Congress on July 10. The chief cause is destruction of habitat, scientists told the House subcommittee on fisheries, wildlife and oceans. They said rising food prices and the push for alternative fuels are putting intense pressure on farmland set aside for conservation. Other killers include invasive plant species that take over native seed and nesting sources, wind turbines located near critical flyways, lighted and glass-encased buildings, lighted cell-phone towers, domestic cats, disease, pesticides and climate change, which also is shrinking habitat ranges. Farmers racing to plant corn for ethanol, which is subsidized by the federal government, and livestock feed are pulling millions of acres out of the nation's largest private land conservation program, the 32 million-acre Conservation Reserve Program, in which the government pays farmers under 10- and 15-year contracts to keep fragile lands out of production. Rising food and energy prices are leading to political pressure from Congress on the Bush administration to allow farmers to break their conservation contracts without penalty. Crashing into Buildings Even "green building" codes that aim to make structures environmentally friendlier, mainly by conserving energy, pay no attention to bird destruction, said Karen Imparato Cotton, a bird crash specialist at the American Bird Conservancy. Cotton said as many as 975 million birds are killed by crashing into buildings each year. Many migrating species of neotropical songbirds, which breed in North America and winter in the Caribbean and South America, are attracted to internal and external building lights as they migrate at night. "The light fields entrap night-migrating birds," Cotton said. "They seem to be reluctant to leave these lit areas and tend to circle within them. As they pile up in the light field, circling the structure, they collide with each other, with the building, or they collapse from exhaustion." New green building codes often call for increased natural lighting that includes more glass, which also induces fatal bird crashes. Neither the private US Green Building Council nor a new Senate bill that aims to promote green building by the federal government includes safe bird design features. "The death of these birds has not been considered an environmental impact of buildings," Cotton said. Simple alterations, such as putting blinking rather than fixed lights on cell phone towers, would minimize the loss of birds, scientists told the panel, but the Federal Communications Commission has not yet acted to make such changes. One-fourth of US land birds are on a watch list, and a third of water birds are at risk, while scientists know too little about night birds such as owls even to assess their populations, said Paul Schmidt, assistant director of the migratory birds program at the US Fish and Wildlife Service. Twenty common bird species have lost 68 percent of their populations in the past 40 years. "A growing proportion of the landscape is occupied by humans," said Wayne Thogmartin, a scientist at the US Geological Survey, which measures bird populations. "A large part is irrevocably lost to birds. The question is what populations do we want to keep. If we want more, we need to find ways to create habitat." Grasslands Threatened About half the nation's wetlands and 70 percent of its prairie grasslands have been lost, scientists told the panel. Grasslands that provide vital bird habitat are now the most threatened landscape on Earth, said John Wiens, chief conservation science officer for PRBO Conservation Science (originally the Point Reyes Bird Observatory), a nongovernmental organization in Petaluma. US grasslands have been converted to large-scale agriculture, he said, and are being further eroded by high food prices. The Agriculture Department recently announced that it will allow farmers to use conservation land for pasture in response to high feed prices. The new farm bill recently passed by Congress had already scaled back the Conservation Reserve Program by 7 million acres and increased incentives to break virgin prairie by allowing farmers to collect federally subsidized crop insurance and disaster payments on newly plowed land. "A lot of sensitive land is being brought back into production," Rep. Ron Kind, D-Wis., said. "The nesting and habitat that migratory birds rely on is in great jeopardy." Twenty common American bird species have lost more than half of their populations since 1960. More than a quarter of American land birds and a third of water birds are on a watch list. Nearly half of neotropical migratory songbirds, which breed in North America and winter in South America and the Caribbean, are considered in severe decline. Among formerly common birds now considered imperiled are: Eastern meadowlark: Since the 1960s, 90 percent decline in New England and 72 percent decline in the rest of its range. Northern bobwhite: 82 percent decline. Found in grasslands mixed with shrubs through eastern United States. Rufous hummingbird: 58 percent decline, found in Northern California, Alaska and Mexico. Whip-poor-will: 57 percent decline. Found in dry, open woodlands in eastern and southwestern United States. Loggerhead shrike: 71 percent decline. Found in short grass in southern half of United States and most of Mexico. Visit PRBO Conservation Science at www.prbo.org/cms/56 for tips on how to help, with California-specific information. Source: National Audubon Society