A recent study of America's bird population says that almost one-third of species are in decline and many are endangered.
Compiling information from a variety of sources, the report examines changes that have occurred over the last four decades.
This most comprehensive report on American bird life caused Interior Secretary Ken Salazar to say Thursday it should be considered "a call to action."
The grassland bird population has declined by 40 percent, the numbers in arid country 30 percent. Some 39 percent of species in coastal areas are also struggling. Forest birds are threatened by urban growth, logging, wildfires and "exotic forest pests and disease," the study noted.
Besides destruction of habitat and pollution, climate change is viewed as a major threat to the bird populations, according to the report, which warned that a "global tragedy" of vanishing species could follow if action is not taken.
On the bright side, the report showed that wetlands conservation has caused populations of herons, ducks and other species to recover handsomely, the New York Times reported.
Information for the analysis was gathered from the U.S. Fish and Wildlife Survey, the U.S. Geological Survey, the American Bird Conservancy and the Cornell Lab of Orinthology. Volunteers from the National Audubon Society were also involved.
The message seems to be that public education about the problem and conservation efforts can help restore bird populations that are dwindling.