Climate change on Earth is creating an unfavorable scenario for the world’s birds. However, it is a concern for scientists that its consequences are manifested even in an area protected from pollution and logging.
Now, a new study published in Science on non-migratory birds in the Amazon has revealed that their bodies have shrunk and their wings have grown from their appearance forty years ago. The research was led by Vitek Jirinec, an ecologist at the Integral Ecology Research Center.
According to the authors, the main culprit would be widespread climate change in the world, which would require other nutritional challenges and physiological for birds in climates that are becoming warmer and drier.
The data were obtained from a total of 15,415 birds from the Amazon rainforest of Brazil, north of Manaus, and belong to 77 species. The habitats of these birds are usually dark and cool soil.
In terms of climate change, the wet seasons in this region have increased by 13% and in the dry ones by 15%. Similarly, the average temperature has increased by 1.8 degrees Fahrenheit in rainy seasons and 2.97 in dry seasons.
The results showed that all species lost an average of 2% of their weight in each decade. That is to say, a 30 gram bird in 1980 would now approach 27.6. They also indicated that 80% of the species developed more extensive wings.
The body reduction of birds due to climate change is explained by the scientific rule of Carl Begman, a 19th century German biologist. According to this principle, mammals and birds are smaller as they live closer to the equator and are larger at the poles. In the birds of the Amazon, a tiny appendix allows them to have a more agile metabolism and thus lose body heat more quickly.
However, the extent of the wings is not entirely clear yet. According to the authors, the transformation of these limbs could help the birds better cope with heat stress by improving the maneuverability of their flight and, therefore, their search for food.
The lightest birds in the sample were those exposed to heat for the longest time and those that lived in dry seasons, where it is more difficult to find food.