Bird species are in "big trouble" worldwide, a sign that the planet's health is also faltering, according to a new report released today at the International Union for Conservation of Nature (IUCN) meeting in Barcelona, Spain.
Not only are rare birds getting rarer, but migratory songbirds, seabirds, and even common backyard birds are also plummeting, according to the State of the World's Birds, a report by the U.K. nonprofit BirdLife International.
The loss could have far-reaching consequences, according to scientists and policy makers.
Like the proverbial canary in a coal mine, the nearly 10,000 known bird species act as "environmental barometers" whose populations can appraise the greater well-being of their habitats.
"There's a serious erosion of biodiversity around us," Leon Bennun, director of science and policy for BirdLife International, said during a briefing at the IUCN's congress.
"It's a signal we should be ...