Global Bird Populations Steadily Declining

Staggering declines in bird populations are taking place around the world. So concludes a study from scientists at multiple institutions, recently published in the journal Annual Review of Environment and Resources.

Loss and degradation of natural habitats and direct over-exploitation of many species are cited as the key threats to avian biodiversity. Climate change is identified as an emerging driver of bird population declines.

The study says approximately 48% of existing bird species worldwide are known or suspected to be undergoing population declines. Populations are stable for 39% of species. Only 6% are showing increasing population trends, and the status of 7% is still unknown. The study authors reviewed changes in avian biodiversity using data from the International Union for Conservation of Nature’s “Red List” to reveal population changes among the world’s 11,000 bird species.

The findings mirror the results of a seminal 2019 study which determined that nearly 3 billion breeding birds have been lost during the past 50 years across the United States and Canada. The lead author of that study is also an author on this global status report.

Despite their findings, study authors say there is hope for avian conservation efforts, but transformative change is needed.

Information is key, and study authors point out that the growth of public participation in bird monitoring and the advent of easy-to-use tools, such as the Cornell Lab’s eBird database, make continental-scale breeding bird surveys, distribution atlases, and abundance models possible and help inform conservation efforts.

This study was conducted by scientists from Manchester Metropolitan University, the Cornell Lab of Ornithology, BirdLife International, the University of Johannesburg, Pontifical Xavierian University, and the Nature Conservation Foundation.

Photos, from above: Corn Bunting by Alex Lees; High or medium-impact threats affecting five globally threatened bird species and the underlying drivers of these threats, data from BirdLife International, graphic courtesy Lees et. al. Annual Review of Environment and Resources; and Spoon-billed Sandpiper by Alex Lees.