Bye-bye, birdies?

Biologists and conservation groups are extremely concerned about a new study showing that a large percentage of the nation’s bird species are in jeopardy.

Comprising data from many expert sources, including the U.S. Fish and Wildlife Service, U.S. Geological Survey and volunteer birders, the study found that about one-third of America’s species of birds are endangered, threatened or in decline, according to The New York Times.

The report included data recorded over the last 40 years. It found that the grassland bird population has plummeted by 40 percent and arid land species fell by 30 percent. In addition, 39 percent of seabird species are declining.

Habitat loss and pollution were cited as a major factor. Global warming is another main threat, the report stated. A silver lining in the report is that populations of some waterfowl, including herons, egrets and ducks, are on the rise thanks to habitat conservation.