The US and Canada have lost more than one in four birds – a total of three billion – since 1970, culminating in what scientists who published a new study are calling a “widespread ecological crisis”.
Researchers observed a 29% decline in bird populations across diverse groups and habitats – from songbirds such as meadowlarks to long-distance migratory birds such as swallows and backyard birds like sparrows.
“Multiple, independent lines of evidence show a massive reduction in the abundance of birds,” said Ken Rosenberg, the study’s lead author and a senior scientist at the Cornell Lab of Ornithology and American Bird Conservancy.Co-author Adam Smith from Environment and Climate Change Canada called the findings a “wake-up call”.
Grassland birds were hit especially hard, with a 53% reduction in population. Shorebirds were already at low numbers and now have lost more than one-third of their population. Radar of the night skies found that the volume of spring migration has dropped 14% in just the last decade.
Not all bird species declined. Raptors and waterfowl showed gains, probably because of focused conservation efforts, including under the Endangered Species Act.