Scientists at Louisiana State University said that birds living in the Amazonian forests are changing their body shape in response to climate change. The authors came to this conclusion by researching how the size of the inhabitants of the Amazonian forests has changed over the past 40 years, Phys.org reports.
According to scientists, due to climate change, the number of birds inhabiting rainforests is decreasing. But that’s not the only thing that is changing. Birds change their tail length and wingspan. This is because the dry season in the region is getting hotter.
Scientists note that birds from the Amazonian rain forests have become smaller, and their wings, on the contrary, have lengthened. Changes have occurred over several generations in response to changing environmental conditions that can lead to nutritional problems.
This is the first study to document such changes in bird species that do not migrate. Scientists studied data on 15,000 individual birds that were caught to measure their body length and weight over 40 years. Each bird was tagged on its foot and released. It turned out that the mass of almost all birds has decreased since the 1980s. Most of the bird species lost about 2% of their mass. Species that weighed an average of 30 grams 40 years ago now weigh 27.5 grams.
The researchers emphasize that the data obtained relate to vast rainforest areas, so it cannot be said that changes in the shape of the birds’ bodies are tied to any particular region.
Scientists studied 77 different species of birds that live in different conditions: close to the cool and dark forest floor or in warmer and sunlit areas. It turned out that birds living in the upper tier and more exposed to the sun and heat were more prone to changes in body shape. They also flew more often than the birds below. The researchers hypothesize that the decrease in body weight allowed them to reduce the load on the wings. Reducing the body and increasing the wingspan also will enable you to use energy more economically in flight and stay cool longer in warm climates.
However, the question of whether Amazonian birds will be able to adapt to drier and hotter conditions in the future is still open. The same question applies to species that inhabit other regions across the earth.
“There are many other studies from other regions that have published data from the 1970s and 1980s that can be compared to current information. Bird measurement protocols are fairly standard. Therefore, if we measure body weight and length, maybe we can get much more data, and better understand the changes in different species and how they change in different systems,” – said one of the study’s authors, Philip Stouffer.
Earlier, American scientists summarized data on the ratio of isotopes of various elements in marine sediments over the past 24 thousand years. As a result, they concluded that modern climate warming has become its fastest change in several tens of thousands of years.
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