Global Declines in Bird Populations—And What You Can Do About It

Global Declines in Bird Populations—And What You Can Do About It

This article relates to Bird School

From his perch among the trees, Adam Nicolson observed the birds of the Sussex woods for over a year, cataloguing his findings in Bird School: A Beginner in the Wood. By the spring migration, however, he noticed that numerous species that should have arrived—that for centuries had arrived at that time—were notably absent: warblers, turtle doves, nightingales, and more. It was a potent example of the global problem of bird extinctions and crashing populations.

In North America, the first-ever large-scale study of bird population changes found a decline of nearly three billion birds since 1970, a figure deemed "staggering" by the scientists involved. And it's not just rare birds like whooping cranes or those that were hunted nearly to extinction by the early 20th century to provide feathers for women's hats. According to the Cornell Lab of Ornithology, 112 species in the United States have lost over 50% of their population, and common species are the ones declining the most.

These declines are driven by many factors, some of which can be addressed at the individual level, and some that are much larger in scope:

• Window collisions: It's estimated that hundreds of millions of birds die each year by colliding with windows. Birds can mistake reflections on the glass as open space, so to mitigate the risk, people can add patterns of dots to glass panes or hang thin cords across their windows, among other interventions. These are important for commercial buildings, too. After a massive migratory wave of birds hit the McCormick Center in Chicago, Illinois one night, killing nearly 1,000 birds, the building added bird-safe window film, and collision deaths declined by 95 percent.
• Hunting: As Nicolson explains in Bird School, songbirds migrating between Europe and Africa are killed by the millions each year. Often sold as culinary delicacies, birds are hunted with huge nets in North Africa and the eastern Mediterranean region. According to Nicolson's research, tens of millions die annually.
• Habitat loss: A massive global problem, habitat loss affects all bird species. In the Sahel region of Africa, for example, desertification, deforestation, and human population growth have reduced habitat for migrating Eurasian species. Wetland destruction, deforestation, and the loss of grasslands globally are also major factors. Conservation efforts can make a difference, and even homeowners can help at the micro level by growing native plants, reducing lawn, and stopping pesticide use.
• Climate change: Similar to habitat loss, the large-scale ecosystem changes due to man-made climate change are a global threat to birds.
• Light pollution: Most birds migrate at night, and light pollution can disorient them, causing them to fly off course and/or become exhausted. Lighted areas also expose them to predators as they travel. Turning off outdoor lights during periods of spring and fall migration is a small but powerful step to improve bird safety.

Another important action people can take is simply to increase their awareness of birds and the pressures facing them. As birding has grown in popularity, more people are discovering the joys of the avian world around them, much like Nicolson did. With greater appreciation comes dedication to protect birds, and by sharing this interest, even more people can start taking action to reverse bird population declines.

Images of the dark-eyed junco (by Cephas, CC BY-SA 3.0) and the red-winged blackbird (by Alan D. Wilson, CC BY-SA 2.5) courtesy of Wikimedia Commons.

Filed under Nature and the Environment

This article relates to Bird School. It first ran in the November 19, 2025 issue of BookBrowse Recommends.