Over the past 40 years, the bird population in the United States and Canada has declined by 29% or almost 3 billion birds. Research was conducted by American scientists at the Cornell Laboratory of Ornithology. According to the results, of the 3 billion dead birds, 90% belong to common families, in particular sparrows, finches and swallows. They play an important role in food chains and support the functioning of ecosystems, such as pest control.
The study noted that bird losses in North America are similar to bird losses in other parts of the world. Co-author of the study, John Sauer, believes that the main factor that affects the extinction of birds is habitat loss, including due to intensive farming and urbanization. Scientists suggest that further climate change will worsen the situation.