"The U.S. State of the Birds" is based on data from three bird censuses, including the annual Christmas bird count organized by the Audubon Society, Interior Secretary Ken Salazar said.
"Just as they were when Rachel Carson published Silent Spring nearly 50 years ago, birds today are a bellwether of the health of land, water and ecosystems," Salazar said. "From shorebirds in New England to warblers in Michigan to songbirds in Hawaii, we are seeing disturbing downward population trends that should set off environmental alarm bells."
Hawaii, where species found nowhere else evolved on the island chain, has more endangered species than anywhere else in the country, the report said. But it also found 40 percent declines in grassland species in the past 40 years, a 30 percent drop in desert birds and a 39 percent decline in ocean species.
There was one note of hope. Many wetlands species like herons and ducks have rebounded because of restoration programs.