Collapsing bird numbers in North America prompt fears of ecological crisis – research

Study using citizen data finds three-quarters of nearly 500 species in decline, with steepest trend in areas where they once thrived

Bird populations across North America are falling most quickly in areas where they are most abundant, according to new research, prompting fears of ecological collapse in previously protected areas.

Analysis of nearly 500 bird species across North America has found that three-quarters are declining across their ranges, with two-thirds of the total shrinking significantly.