The populations of nearly two dozen common American birds — the fence-sitting meadowlark, the frenetic Rufous hummingbird and the whippoorwill with its haunting call — are half what they were 40 years ago, a new analysis found.

The northern bobwhite and its familiar wake-up whistle once seemed to be everywhere in the East. Last Christmas, volunteer bird counters could find only three of them and only 18 Eastern meadowlarks in Massachusetts. The northern bobwhite had the biggest drop among common birds. In 1967, there were 31 million of the plump ground-loving bird. Now they number closer to 5.5 million.

Many of the species in decline depend on open grassy habitats that are disappearing because of suburban sprawl. Climate change and invasive species are to blame, too.

[Read](http://www.msnbc.msn.com/id/19225721/ “Read the Story”) (AP via MSNBC)