U.S. bird populations are experiencing alarming declines due to factors such as habitat loss and climate change, according to a new report identifying 112 species that have reached a "tipping point," including 42 with perilously low numbers and steep downward trends.

The U.S. bird population is declining at an alarming rate, according to a report published Thursday by an alliance of science and conservation groups. Habitat loss and climate change are among the key contributing factors to the bird population losses,