Report that about 3 billion birds have disappeared in North America in 50 years
Due to overhunting by humans and climate change, many species have faced crises such as declining populations and extinction.
Decline of the North American avifauna | Science
https://doi.org/10.1126/science.aaw1313
New Research Shows Over a Third of North American Birds Have Disappeared in the Past 50 Years.
Although North America is thought to be home to about billions of birds with tens of millions of species, it has been difficult to measure the actual population of these constantly migrating birds. However, the field of bird research is progressing day and night, and today it is possible to make measurements based on information from citizens such as radar images, satellite photos, and the online database ' eBird '.
Using these data, Smith made calculations that included population estimates for 529 bird species, ranging from common bird species such as sparrows and robins to rare and rare species. They found that the populations of these species have declined significantly across the North American continent.
As a result of the survey, it was found that about 2.913 billion birds disappeared in about 50 years from the beginning of 1970 to 2019. According to Mr. Smith, the bird population has been in a continuous and rapid decline for a long period of 50 years, and the fact that about one-third of the adult bird population in North America has disappeared. Did.
Among the birds that continue to decline, grassland birds have been severely affected, with their populations declining by more than 50%. The population decline is said to be due to the expansion of farms, which has transformed the varied grasslands into vast cultivated lands. It is speculated that birds such as birds , western rockbirds , and horned larks have disappeared.
Due to deforestation by humans, the number of birds living in the forest has also decreased significantly, and it is believed that 500 million birds, which is one-third of the population of warblers and woodpeckers, have disappeared. In addition, population declines have been confirmed for birds such as sparrows, black thrushes , and starlings that live close to human activity areas, and it has been reported that 90% of the population has been lost in 50 years.
According to Smith, research focused on common birds such as sparrows and black thrushes is limited, and studies on other birds in more critical situations dominate. As such, there is a lack of urgency to address population declines in common birds.
Mr. Smith said, ``In a short span of 50 years, which is less than the human lifetime, we lost about 30% of the total bird population,'' he said, and the future collapse of the ecosystem. He stresses the need to urgently address the threat of declining populations in order to avoid
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