Many people think that the Amazon forest is a great place to live for natural creatures, but even here, the effects of climate change are still happening and growing heavier. Recently, a study found that many sensitive bird species in the Amazon region are starting to change in response to increasingly warmer temperatures.
New research examined four decades of data on Amazon birds and found that as the Amazon becomes hotter and arid, some bird species appear to be changing physically.
Birds are often seen as key species, indicative of the overall health of ecosystems, so scientists are particularly interested in how they respond to climate change. In general, things are not good. A 2019 report by the National Audubon Society found that more than two-thirds of North American bird species could become extinct by 2100 if global warming trends continue at current rates.
In the new study, the researchers collected the largest data set to date on Amazon resident birds, representing 77 non-migratory species and spanning 40 years from 1979 to 2019. They report 12 in the journal Science Advances that 36 species have lost a significant amount of weight, up to 2% of their body weight per decade since 1980. Meanwhile, all species have lost mass. On average body mass, one-third grow longer wings.
The course of the study has seen average temperatures in the region increase, while rainfall decreases. Temperature increases by 1°C in the rainy season and 1.65°C in the dry season. Rainfall increases by 13% in the wet season but decreases by 15% in the dry season, making the climate drier and hotter.
The researchers focused on non-migratory birds, which helps rule out factors such as exposure to different habitats, which are responsible for the physical changes. The birds in the study spent their entire lives in the undisturbed rainforest, right under the trees.
Why did birds change to have a smaller body and longer wings?
The researchers aren’t sure how changes in wing length benefit them either, but the birds with smaller bodies can more easily stay cool. In general, smaller animals have a greater ratio of surface area to body size, so they disperse heat faster than larger animals. Less food, such as fruit or insects, in dry weather can also lead to a smaller body size.
As for birds developing longer wings, the researchers hypothesize that this saves the bird more energy in flight, as it can spend more time gliding than flapping its wings. help them fly farther to feed. However, this needs further study.
“We think of Amazonia as a symbol of terrestrial biodiversity, a mysterious place, teeming with life, untouched by humans, away from deforestation. But that doesn’t seem to be the case.” shared by researchers.