Common US birds disappearing

The populations of 20 common US birds–from the meadowlark to the whippoorwill with its haunting call–are half what they were 40 years ago, according to an analysis released on June 14. Suburban sprawl, climate change and invasive species are largely to blame, said the study's author, Greg Butcher, of the National Audubon Society. "Most of these we don't expect will go extinct," he said. "We think they reflect other things that are happening in the environment that we should be worried about." The study is a new analysis of 40 years of data collected by the National Audubon Society and the US Geological Survey. The dramatic declines are attributed to the loss of grasslands, healthy forests and wetlands, and other critical habitats from multiple environmental threats such as sprawl, energy development and the spread of industrialized agriculture. The study notes global warming is damaging some key habitats and speeding the spread of invasive species that cause further declines. Mounting demand for corn-based ethanol is expected to result in increased use of marginal farmland that now serves as important bird habitat. Since 1967 the average population of the common birds in steepest decline has fallen by 68 percent; some individual species nose-dived as much as 80 percent. All 20 birds on the national Common Birds in Decline list lost at least half their populations in just four decades, Audubon says.