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Добавлено: Пт Дек 25, 2020 12:45 pm Заголовок сообщения: Smaller North American birds Believed to be the result of 'g |
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There is a study 168 where the bird remains in Chicago were measured. Found that in the past several decades These birds have decreased in size. Scholars believe this is a biologically concrete effect of rising global temperatures.
Reuters reports that since 1978 researchers have collected tens of thousands of birds. During the spring and autumn they fly. These birds often die from hitting buildings in Greater Chicago. They found that the collected birds were smaller.
The details of this study are drawn from a collection of data between 1978 and 2016, where the study collected 70,716 carcasses of birds killed in the crash in Chicago. They come from 52 species, most of them in songbirds such as sparrows, youngsters, and subspecies, which are bred in temperate regions of North America. Before flying immigrants to spend the winter in the southern area of Chicago
The researchers measured the scale and weighed it. It was found that the average size of the carcasses of birds collected has continued to decline. However, measuring the length from both wing tips showed that the mean increased.
Researchers pinpoint the smaller size of the North American bird It may be believed that this is a worldwide phenomenon. Comes from the effects of the rising global temperature They made reference to Bergmann's rule, which explains that cold-dwelling animals are larger than close-knit species that live in the tropics. It can be concluded that the body size tends to shrink as the temperature increases.
Over the past four decades, the carcasses of 52 bird species have declined. The overall average weight was decreased by 2.6%, the length of the femur was reduced by 2.4%, while the length from both wing tips was increased by 1.3%. The physical adaptation of these birds is to preserve the species. Causing them to migrate long distances even though their bodies are smaller
On the lead side of the study, Brian Weeks, a biologist at the University of Michigan Faculty of Environment and Sustainability, said: "Climate change is transforming both the shape and size of these organisms."
He also added that “Humanity is moving the world with unprecedented speed and prosperity. The biological response of nature as a whole Are adapting to the changing environment as well "
And Dave Willard, Special Agent at the Field Museum in Chicago. The person who inspected the carcass said that “We all know that global temperatures are rising. And today we can see a clear example For the effects it occurs in nature "
Another study published this past September. Provides worrying new information for North American birds. Stating that the number of bird populations in the United States And Canada Decreased from the year 1970 by 29 percent or total 2.9 billion. |
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