More than half of Earth’s migratory bird species are declining

THE CONVERSATION • July 23, 2026

Every year, billions of migratory birds connect the world’s continents, oceans and ecosystems as they undertake epic journeys between their foraging habitats and their breeding grounds. Today, many species are in trouble. Their migrations remain among nature’s greatest spectacles, but the birds themselves are increasingly at risk as the habitats and ecological connections they depend upon are lost or degraded and threats to their survival and ability to reproduce increase. We just published a comprehensive assessment of the status, threats and conservation efforts involving more than 3,380 of Earth’s migratory bird species. The results are sobering. We found that more than half of the world’s migratory bird species are declining because of an array of threats.